diff --git a/azure-pipelines/e2e_ports/vcpkg-internal-e2e-test-port2/portfile.cmake b/azure-pipelines/e2e_ports/vcpkg-internal-e2e-test-port2/portfile.cmake
new file mode 100644
index 0000000000..065116c276
--- /dev/null
+++ b/azure-pipelines/e2e_ports/vcpkg-internal-e2e-test-port2/portfile.cmake
@@ -0,0 +1 @@
+set(VCPKG_POLICY_EMPTY_PACKAGE enabled)
diff --git a/azure-pipelines/e2e_ports/vcpkg-internal-e2e-test-port2/vcpkg.json b/azure-pipelines/e2e_ports/vcpkg-internal-e2e-test-port2/vcpkg.json
new file mode 100644
index 0000000000..b3806dacc1
--- /dev/null
+++ b/azure-pipelines/e2e_ports/vcpkg-internal-e2e-test-port2/vcpkg.json
@@ -0,0 +1,4 @@
+{
+	"name": "vcpkg-internal-e2e-test-port2",
+	"version-string": "1.0.0"
+}
diff --git a/azure-pipelines/end-to-end-tests-dir/registries.ps1 b/azure-pipelines/end-to-end-tests-dir/registries.ps1
index 0a1f39e35c..2c16c44fdc 100644
--- a/azure-pipelines/end-to-end-tests-dir/registries.ps1
+++ b/azure-pipelines/end-to-end-tests-dir/registries.ps1
@@ -64,17 +64,26 @@ try
         '-c', 'core.autocrlf=false'
     )
 
+    $gitMainBranch = 'main'
+    $gitSecondaryBranch = 'secondary'
+
     $CurrentTest = 'git init .'
     git @gitConfigOptions init .
     Throw-IfFailed
+
+    # Create git registry with vcpkg-internal-e2e-test-port in the main branch
+    $CurrentTest = 'git switch --orphan'
+    git @gitConfigOptions switch --orphan $gitMainBranch
+    Throw-IfFailed
+
     Copy-Item -Recurse -LiteralPath "$PSScriptRoot/../e2e_ports/vcpkg-internal-e2e-test-port" -Destination .
     New-Item -Path './vcpkg-internal-e2e-test-port/foobar' -Value 'this is just to get a distinct git tree'
 
     $CurrentTest = 'git add -A'
     git @gitConfigOptions add -A
     Throw-IfFailed
-    $CurrentTest = 'git commit'
-    git @gitConfigOptions commit -m 'initial commit'
+    $CurrentTest = 'git commit -m'
+    git @gitConfigOptions commit -m 'add vcpkg-internal-e2e-test-port'
     Throw-IfFailed
 
     $vcpkgInternalE2eTestPortGitTree = git rev-parse 'HEAD:vcpkg-internal-e2e-test-port'
@@ -103,12 +112,65 @@ try
     $CurrentTest = 'git add -A'
     git @gitConfigOptions add -A
     Throw-IfFailed
-    $CurrentTest = 'git commit'
+    $CurrentTest = 'git commit --amend --no-edit'
+    git @gitConfigOptions commit --amend --no-edit
+    Throw-IfFailed
+
+    $gitMainBaselineCommit = git rev-parse HEAD
+    $gitMainRefVersionsObject = git rev-parse HEAD:versions
+
+    # Create git registry with vcpkg-internal-e2e-test-port2 in the secondary branch
+
+    $CurrentTest = 'git switch --orphan'
+    git @gitConfigOptions switch --orphan $gitSecondaryBranch
+    Throw-IfFailed
+
+    Copy-Item -Recurse -LiteralPath "$PSScriptRoot/../e2e_ports/vcpkg-internal-e2e-test-port2" -Destination .
+    New-Item -Path './vcpkg-internal-e2e-test-port2/foobaz' -Value 'this is just to get a distinct git tree'
+
+    $CurrentTest = 'git add -A'
+    git @gitConfigOptions add -A
+    Throw-IfFailed
+    $CurrentTest = 'git commit -m'
+    git @gitConfigOptions commit -m 'add vcpkg-internal-e2e-test-port2'
+    Throw-IfFailed
+
+    $vcpkgInternalE2eTestPort2GitTree = git rev-parse 'HEAD:vcpkg-internal-e2e-test-port2'
+    $vcpkgInternalE2eTestPortVersionsJson = @{
+        "versions" = @(
+            @{
+                "version-string" = "1.0.0";
+                "git-tree" = $vcpkgInternalE2eTestPort2GitTree
+            }
+        )
+    }
+    $vcpkgBaseline = @{
+        "default" = @{
+            "vcpkg-internal-e2e-test-port2" = @{
+                "baseline" = "1.0.0"
+            }
+        }
+    }
+
+    New-Item -Path './versions' -ItemType Directory
+    New-Item -Path './versions/v-' -ItemType Directory
+
+    New-Item -Path './versions/baseline.json' -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgBaseline)
+    New-Item -Path './versions/v-/vcpkg-internal-e2e-test-port2.json' -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgInternalE2eTestPortVersionsJson)
+
+    $CurrentTest = 'git add -A'
+    git @gitConfigOptions add -A
+    Throw-IfFailed
+    $CurrentTest = 'git commit --amend --no-edit'
     git @gitConfigOptions commit --amend --no-edit
     Throw-IfFailed
 
-    $gitBaselineCommit = git rev-parse HEAD
-    $gitRefVersionsObject = git rev-parse HEAD:versions
+    $gitSecondaryBaselineCommit = git rev-parse HEAD
+    $gitSecondaryRefVersionsObject = git rev-parse HEAD:versions
+
+    $CurrentTest = 'git switch'
+    git @gitConfigOptions switch $gitMainBranch
+    Throw-IfFailed
 }
 finally
 {
@@ -117,18 +179,6 @@ finally
 
 # actually test the registries
 Write-Trace "actually test the registries"
-$vcpkgJson = @{
-    "name" = "manifest-test";
-    "version-string" = "1.0.0";
-    "dependencies" = @(
-        "vcpkg-internal-e2e-test-port"
-    );
-    # Use versioning features without a builtin-baseline
-    "overrides" = @(@{
-        "name" = "unused";
-        "version" = "0";
-    })
-}
 
 # test the filesystem registry
 Write-Trace "test the filesystem registry"
@@ -140,9 +190,18 @@ $manifestDir = (Get-Item $manifestDir).FullName
 Push-Location $manifestDir
 try
 {
-    New-Item -Path 'vcpkg.json' -ItemType File `
-        -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgJson)
-
+    $vcpkgJson = @{
+        "name" = "manifest-test";
+        "version-string" = "1.0.0";
+        "dependencies" = @(
+            "vcpkg-internal-e2e-test-port"
+        );
+        # Use versioning features without a builtin-baseline
+        "overrides" = @(@{
+            "name" = "unused";
+            "version" = "0";
+        })
+    }
     $vcpkgConfigurationJson = @{
         "default-registry" = $null;
         "registries" = @(
@@ -153,6 +212,8 @@ try
             }
         )
     }
+    New-Item -Path 'vcpkg.json' -ItemType File `
+        -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgJson)
     New-Item -Path 'vcpkg-configuration.json' -ItemType File `
         -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgConfigurationJson)
 
@@ -174,8 +235,19 @@ $manifestDir = (Get-Item $manifestDir).FullName
 Push-Location $manifestDir
 try
 {
-    New-Item -Path 'vcpkg.json' -ItemType File `
-        -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgJson)
+    $vcpkgJson = @{
+        "name" = "manifest-test";
+        "version-string" = "1.0.0";
+        "dependencies" = @(
+            "vcpkg-internal-e2e-test-port",
+            "vcpkg-internal-e2e-test-port2"
+        );
+        # Use versioning features without a builtin-baseline
+        "overrides" = @(@{
+            "name" = "unused";
+            "version" = "0";
+        })
+    }
 
     $vcpkgConfigurationJson = @{
         "default-registry" = $null;
@@ -183,25 +255,44 @@ try
             @{
                 "kind" = "git";
                 "repository" = $gitRegistryUpstream;
-                "baseline" = $gitBaselineCommit;
-                "packages" = @( "vcpkg-internal-e2e-test-port" )
+                "baseline" = $gitMainBaselineCommit;
+                 "packages" = @( "vcpkg-internal-e2e-test-port" )
+            },
+            @{
+                "kind" = "git";
+                "repository" = $gitRegistryUpstream;
+                "reference" = $gitSecondaryBranch;
+                "baseline" = $gitSecondaryBaselineCommit;
+                 "packages" = @( "vcpkg-internal-e2e-test-port2" )
             }
         )
     }
+
+    New-Item -Path 'vcpkg.json' -ItemType File `
+        -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgJson)
+
     New-Item -Path 'vcpkg-configuration.json' -ItemType File `
         -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgConfigurationJson)
 
     Run-Vcpkg install @builtinRegistryArgs '--feature-flags=registries,manifests' --dry-run
     Throw-IfFailed
     Require-FileExists $env:X_VCPKG_REGISTRIES_CACHE/git-trees/$vcpkgInternalE2eTestPortGitTree
+    Require-FileExists $env:X_VCPKG_REGISTRIES_CACHE/git-trees/$vcpkgInternalE2eTestPort2GitTree
     # This is both the selected baseline as well as the current HEAD
-    Require-FileExists $env:X_VCPKG_REGISTRIES_CACHE/git-trees/$gitRefVersionsObject
+    Require-FileExists $env:X_VCPKG_REGISTRIES_CACHE/git-trees/$gitMainRefVersionsObject
+    Require-FileExists $env:X_VCPKG_REGISTRIES_CACHE/git-trees/$gitSecondaryRefVersionsObject
     # Dry run does not create a lockfile
     Require-FileNotExists $installRoot/vcpkg/vcpkg-lock.json
 
     Run-Vcpkg install @builtinRegistryArgs '--feature-flags=registries,manifests'
     Throw-IfFailed
-    Require-FileEquals $installRoot/vcpkg/vcpkg-lock.json "{`n  $(ConvertTo-Json $gitRegistryUpstream): `"$gitBaselineCommit`"`n}`n"
+
+    $expectedVcpkgLockJson = "{$(ConvertTo-Json $gitRegistryUpstream):{
+        `"HEAD`" : `"$gitMainBaselineCommit`",
+        `"$gitSecondaryBranch`" : `"$gitSecondaryBaselineCommit`"
+    }}"
+
+    Require-JsonFileEquals $installRoot/vcpkg/vcpkg-lock.json $expectedVcpkgLockJson
 
     # Using the lock file means we can reinstall without pulling from the upstream registry
     $vcpkgConfigurationJson = @{
@@ -210,18 +301,34 @@ try
             @{
                 "kind" = "git";
                 "repository" = "/"; # An invalid repository
-                "baseline" = $gitBaselineCommit;
-                "packages" = @( "vcpkg-internal-e2e-test-port" )
+                "baseline" = $gitMainBaselineCommit;
+                 "packages" = @( "vcpkg-internal-e2e-test-port" )
+            },
+            @{
+                "kind" = "git";
+                "repository" = "/"; # An invalid repository
+                "reference" = $gitSecondaryBranch;
+                "baseline" = $gitSecondaryBaselineCommit;
+                 "packages" = @( "vcpkg-internal-e2e-test-port2" )
             }
         )
     }
 
+    Set-Content -Path 'vcpkg-configuration.json' `
+        -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgConfigurationJson)
+
     Remove-Item -Recurse -Force $installRoot -ErrorAction SilentlyContinue
     Require-FileNotExists $installRoot
     New-Item -Path $installRoot/vcpkg -ItemType Directory
     # We pre-seed the install root with a lockfile for the invalid repository, so it isn't actually fetched from
-    New-Item -Path $installRoot/vcpkg/vcpkg-lock.json -ItemType File `
-        -Value "{`n  `"/`": `"$gitBaselineCommit`"`n}`n"
+    $vcpkgLockJson = @{
+        "/" = @{
+            "HEAD" = $gitMainBaselineCommit; 
+            $gitSecondaryBranch = $gitSecondaryBaselineCommit  
+        } 
+    }
+   New-Item -Path $installRoot/vcpkg/vcpkg-lock.json -ItemType File `
+        -Value (ConvertTo-Json -Depth 5 -InputObject $vcpkgLockJson)
     Run-Vcpkg install @builtinRegistryArgs '--feature-flags=registries,manifests'
     Throw-IfFailed
 }
diff --git a/azure-pipelines/end-to-end-tests-prelude.ps1 b/azure-pipelines/end-to-end-tests-prelude.ps1
index 4d7cf033d0..bdae1232a1 100644
--- a/azure-pipelines/end-to-end-tests-prelude.ps1
+++ b/azure-pipelines/end-to-end-tests-prelude.ps1
@@ -42,16 +42,21 @@ function Require-FileExists {
     }
 }
 
-function Require-FileEquals {
+function Require-JsonFileEquals {
     [CmdletBinding()]
     Param(
         [string]$File,
-        [string]$Content
+        [string]$Json
     )
     Require-FileExists $File
-    if ((Get-Content $File -Raw) -ne $Content) {
+    $ExpectedJson = $Json | ConvertFrom-Json | ConvertTo-Json -Compress
+    $ActualJson = Get-Content $File | ConvertFrom-Json | ConvertTo-Json -Compress
+
+    if ($ActualJson -ne $ExpectedJson) {
         Write-Stack
-        throw "'$Script:CurrentTest' file '$File' did not have the correct contents"
+        throw "'$Script:CurrentTest' file '$File' did not have the correct contents`n
+                Expected: $ExpectedJson`n
+                Actual:   $ActualJson"
     }
 }
 
diff --git a/azure-pipelines/end-to-end-tests.ps1 b/azure-pipelines/end-to-end-tests.ps1
old mode 100644
new mode 100755
diff --git a/include/vcpkg/registries.h b/include/vcpkg/registries.h
index d4b91755c2..4a478b8f3c 100644
--- a/include/vcpkg/registries.h
+++ b/include/vcpkg/registries.h
@@ -24,24 +24,28 @@ namespace vcpkg
     {
         struct EntryData
         {
-            std::string value;
+            std::string reference;
+            std::string commit_id;
             bool stale;
         };
+
+        using LockDataType = std::multimap<std::string, EntryData, std::less<>>;
         struct Entry
         {
             LockFile* lockfile;
-            std::map<std::string, EntryData, std::less<>>::iterator data;
+            LockDataType::iterator data;
 
-            const std::string& value() const { return data->second.value; }
+            const std::string& reference() const { return data->second.reference; }
+            const std::string& commit_id() const { return data->second.commit_id; }
             bool stale() const { return data->second.stale; }
             const std::string& uri() const { return data->first; }
 
             void ensure_up_to_date(const VcpkgPaths& paths) const;
         };
 
-        Entry get_or_fetch(const VcpkgPaths& paths, StringView key);
+        Entry get_or_fetch(const VcpkgPaths& paths, StringView repo, StringView reference);
 
-        std::map<std::string, EntryData, std::less<>> lockdata;
+        LockDataType lockdata;
         bool modified = false;
     };
 
diff --git a/src/vcpkg-test/registries.cpp b/src/vcpkg-test/registries.cpp
index 71b0537829..4e0b9f2c49 100644
--- a/src/vcpkg-test/registries.cpp
+++ b/src/vcpkg-test/registries.cpp
@@ -182,6 +182,23 @@ TEST_CASE ("registry_parsing", "[registries]")
         CHECK(!r.errors().empty());
     }
 
+    test_json = parse_json(R"json(
+{
+    "kind": "git",
+    "repository": "abc",
+    "baseline": "123",
+    "reference": "abc/def"
+}
+    )json");
+    {
+        Json::Reader r;
+        auto registry_impl = r.visit(test_json, *registry_impl_des);
+        REQUIRE(registry_impl);
+        CHECK(*registry_impl.get());
+        INFO(Strings::join("\n", r.errors()));
+        CHECK(r.errors().empty());
+    }
+
     test_json = parse_json(R"json(
 {
     "kind": "git",
diff --git a/src/vcpkg/registries.cpp b/src/vcpkg/registries.cpp
index bc376b5d00..412f5efa0d 100644
--- a/src/vcpkg/registries.cpp
+++ b/src/vcpkg/registries.cpp
@@ -50,8 +50,8 @@ namespace
 
     struct GitRegistry final : RegistryImplementation
     {
-        GitRegistry(std::string&& repo, std::string&& baseline)
-            : m_repo(std::move(repo)), m_baseline_identifier(std::move(baseline))
+        GitRegistry(std::string&& repo, std::string&& reference, std::string&& baseline)
+            : m_repo(std::move(repo)), m_reference(std::move(reference)), m_baseline_identifier(std::move(baseline))
         {
         }
 
@@ -69,7 +69,7 @@ namespace
         LockFile::Entry get_lock_entry(const VcpkgPaths& paths) const
         {
             return m_lock_entry.get(
-                [this, &paths]() { return paths.get_installed_lockfile().get_or_fetch(paths, m_repo); });
+                [this, &paths]() { return paths.get_installed_lockfile().get_or_fetch(paths, m_repo, m_reference); });
         }
 
         Path get_versions_tree_path(const VcpkgPaths& paths) const
@@ -78,7 +78,7 @@ namespace
                 auto e = get_lock_entry(paths);
                 e.ensure_up_to_date(paths);
                 auto maybe_tree =
-                    paths.git_find_object_id_for_remote_registry_path(e.value(), registry_versions_dir_name);
+                    paths.git_find_object_id_for_remote_registry_path(e.commit_id(), registry_versions_dir_name);
                 if (!maybe_tree)
                 {
                     LockGuardPtr<Metrics>(g_metrics)->track_property("registries-error-no-versions-at-commit",
@@ -87,7 +87,7 @@ namespace
                         VCPKG_LINE_INFO,
                         "Error: could not find the git tree for `versions` in repo `%s` at commit `%s`: %s",
                         m_repo,
-                        e.value(),
+                        e.commit_id(),
                         maybe_tree.error());
                 }
                 auto maybe_path = paths.git_checkout_object_from_remote_registry(*maybe_tree.get());
@@ -118,7 +118,7 @@ namespace
             if (!m_stale_versions_tree.has_value())
             {
                 auto maybe_tree =
-                    paths.git_find_object_id_for_remote_registry_path(e.value(), registry_versions_dir_name);
+                    paths.git_find_object_id_for_remote_registry_path(e.commit_id(), registry_versions_dir_name);
                 if (!maybe_tree)
                 {
                     // This could be caused by git gc or otherwise -- fall back to full fetch
@@ -136,6 +136,7 @@ namespace
         }
 
         std::string m_repo;
+        std::string m_reference;
         std::string m_baseline_identifier;
         DelayedInit<LockFile::Entry> m_lock_entry;
         mutable Optional<Path> m_stale_versions_tree;
@@ -507,7 +508,7 @@ namespace
                     "commit SHA (40 lowercase hexadecimal characters).\n"
                     "The current HEAD of that repo is \"%s\".\n",
                     m_repo,
-                    e.value());
+                    e.commit_id());
             }
 
             auto path_to_baseline = Path(registry_versions_dir_name) / "baseline.json";
@@ -717,6 +718,7 @@ namespace
         constexpr static StringLiteral BASELINE = "baseline";
         constexpr static StringLiteral PATH = "path";
         constexpr static StringLiteral REPO = "repository";
+        constexpr static StringLiteral REFERENCE = "reference";
 
         constexpr static StringLiteral KIND_BUILTIN = "builtin";
         constexpr static StringLiteral KIND_FILESYSTEM = "filesystem";
@@ -737,6 +739,7 @@ namespace
     constexpr StringLiteral RegistryImplDeserializer::BASELINE;
     constexpr StringLiteral RegistryImplDeserializer::PATH;
     constexpr StringLiteral RegistryImplDeserializer::REPO;
+    constexpr StringLiteral RegistryImplDeserializer::REFERENCE;
     constexpr StringLiteral RegistryImplDeserializer::KIND_BUILTIN;
     constexpr StringLiteral RegistryImplDeserializer::KIND_FILESYSTEM;
     constexpr StringLiteral RegistryImplDeserializer::KIND_GIT;
@@ -758,7 +761,7 @@ namespace
 
     View<StringView> RegistryImplDeserializer::valid_fields() const
     {
-        static const StringView t[] = {KIND, BASELINE, PATH, REPO};
+        static const StringView t[] = {KIND, BASELINE, PATH, REPO, REFERENCE};
         return t;
     }
     View<StringView> valid_builtin_fields()
@@ -786,6 +789,7 @@ namespace
             RegistryImplDeserializer::KIND,
             RegistryImplDeserializer::BASELINE,
             RegistryImplDeserializer::REPO,
+            RegistryImplDeserializer::REFERENCE,
             RegistryDeserializer::PACKAGES,
         };
         return t;
@@ -839,10 +843,17 @@ namespace
             Json::StringDeserializer repo_des{"a git repository URL"};
             r.required_object_field("a git registry", obj, REPO, repo, repo_des);
 
+            std::string ref;
+            Json::StringDeserializer ref_des{"a git reference (for example, a branch)"};
+            if (!r.optional_object_field(obj, REFERENCE, ref, ref_des))
+            {
+                ref = "HEAD";
+            }
+
             std::string baseline;
             r.required_object_field("a git registry", obj, BASELINE, baseline, baseline_deserializer);
 
-            res = std::make_unique<GitRegistry>(std::move(repo), std::move(baseline));
+            res = std::make_unique<GitRegistry>(std::move(repo), std::move(ref), std::move(baseline));
         }
         else
         {
@@ -866,6 +877,7 @@ namespace
             RegistryImplDeserializer::BASELINE,
             RegistryImplDeserializer::PATH,
             RegistryImplDeserializer::REPO,
+            RegistryImplDeserializer::REFERENCE,
             PACKAGES,
         };
         return t;
@@ -1130,25 +1142,34 @@ namespace vcpkg
         return r.array_elements(arr, underlying);
     }
 
-    LockFile::Entry LockFile::get_or_fetch(const VcpkgPaths& paths, StringView key)
+    LockFile::Entry LockFile::get_or_fetch(const VcpkgPaths& paths, StringView repo, StringView reference)
     {
-        auto it = lockdata.find(key);
-        if (it == lockdata.end())
+        auto range = lockdata.equal_range(repo);
+        auto it = std::find_if(range.first, range.second, [&reference](const LockDataType::value_type& repo2entry) {
+            return repo2entry.second.reference == reference;
+        });
+
+        if (it == range.second)
         {
-            print2("Fetching registry information from ", key, "...\n");
-            auto x = paths.git_fetch_from_remote_registry(key, "HEAD");
-            it = lockdata.emplace(key.to_string(), EntryData{x.value_or_exit(VCPKG_LINE_INFO), false}).first;
+            print2("Fetching registry information from ", repo, " (", reference, ")...\n");
+            auto x = paths.git_fetch_from_remote_registry(repo, reference);
+            it = lockdata.emplace(repo.to_string(),
+                                  EntryData{reference.to_string(), x.value_or_exit(VCPKG_LINE_INFO), false});
             modified = true;
         }
+
         return {this, it};
     }
     void LockFile::Entry::ensure_up_to_date(const VcpkgPaths& paths) const
     {
         if (data->second.stale)
         {
-            print2("Fetching registry information from ", data->first, "...\n");
-            data->second.value =
-                paths.git_fetch_from_remote_registry(data->first, "HEAD").value_or_exit(VCPKG_LINE_INFO);
+            StringView repo(data->first);
+            StringView reference(data->second.reference);
+            print2("Fetching registry information from ", repo, " (", reference, ")...\n");
+
+            data->second.commit_id =
+                paths.git_fetch_from_remote_registry(repo, reference).value_or_exit(VCPKG_LINE_INFO);
             data->second.stale = false;
             lockfile->modified = true;
         }
diff --git a/src/vcpkg/vcpkgpaths.cpp b/src/vcpkg/vcpkgpaths.cpp
index fb7db74bcf..8bb1049906 100644
--- a/src/vcpkg/vcpkgpaths.cpp
+++ b/src/vcpkg/vcpkgpaths.cpp
@@ -509,6 +509,63 @@ namespace vcpkg
         });
     }
 
+    static LockFile::LockDataType lockdata_from_json_object(const Json::Object& obj)
+    {
+        LockFile::LockDataType ret;
+        for (auto&& repo_to_ref_info_value : obj)
+        {
+            auto repo = repo_to_ref_info_value.first;
+            const auto& ref_info_value = repo_to_ref_info_value.second;
+
+            if (!ref_info_value.is_object())
+            {
+                Debug::print("Lockfile value for key '", repo, "' was not an object\n");
+                return ret;
+            }
+
+            for (auto&& reference_to_commit : ref_info_value.object())
+            {
+                auto reference = reference_to_commit.first;
+                const auto& commit = reference_to_commit.second;
+
+                if (!commit.is_string())
+                {
+                    Debug::print("Lockfile value for key '", reference, "' was not a string\n");
+                    return ret;
+                }
+                auto sv = commit.string();
+                if (!is_git_commit_sha(sv))
+                {
+                    Debug::print("Lockfile value for key '", reference, "' was not a git commit sha\n");
+                    return ret;
+                }
+                ret.emplace(repo.to_string(), LockFile::EntryData{reference.to_string(), sv.to_string(), true});
+            }
+        }
+        return ret;
+    }
+
+    static Json::Object lockdata_to_json_object(const LockFile::LockDataType& lockdata)
+    {
+        Json::Object obj;
+        for (auto it = lockdata.begin(); it != lockdata.end();)
+        {
+            const auto& repo = it->first;
+            auto repo_info_range = lockdata.equal_range(repo);
+
+            Json::Object repo_info;
+            for (auto repo_it = repo_info_range.first; repo_it != repo_info_range.second; ++repo_it)
+            {
+                repo_info.insert(repo_it->second.reference, Json::Value::string(repo_it->second.commit_id));
+            }
+            repo_info.sort_keys();
+            obj.insert(repo, std::move(repo_info));
+            it = repo_info_range.second;
+        }
+
+        return obj;
+    }
+
     static LockFile load_lockfile(const Filesystem& fs, const Path& p)
     {
         LockFile ret;
@@ -522,26 +579,14 @@ namespace vcpkg
         else if (auto lock_contents = maybe_lock_contents.get())
         {
             auto& doc = lock_contents->first;
-            if (doc.is_object())
+            if (!doc.is_object())
             {
-                for (auto&& x : doc.object())
-                {
-                    if (!x.second.is_string())
-                    {
-                        Debug::print("Lockfile value for key '", x.first, "' was not a string\n");
-                        return ret;
-                    }
-                    auto sv = x.second.string();
-                    if (!is_git_commit_sha(sv))
-                    {
-                        Debug::print("Lockfile value for key '", x.first, "' was not a git commit sha\n");
-                        return ret;
-                    }
-                    ret.lockdata.emplace(x.first.to_string(), LockFile::EntryData{sv.to_string(), true});
-                }
+                Debug::print("Lockfile was not an object\n");
                 return ret;
             }
-            Debug::print("Lockfile was not an object\n");
+
+            ret.lockdata = lockdata_from_json_object(doc.object());
+
             return ret;
         }
         else
@@ -559,6 +604,7 @@ namespace vcpkg
         }
         return *m_pimpl->m_installed_lock.get();
     }
+
     void VcpkgPaths::flush_lockfile() const
     {
         // If the lock file was not loaded, no need to flush it.
@@ -566,11 +612,9 @@ namespace vcpkg
         // lockfile was not modified, no need to write anything to disk.
         const auto& lockfile = *m_pimpl->m_installed_lock.get();
         if (!lockfile.modified) return;
-        Json::Object obj;
-        for (auto&& data : lockfile.lockdata)
-        {
-            obj.insert(data.first, Json::Value::string(data.second.value));
-        }
+
+        auto obj = lockdata_to_json_object(lockfile.lockdata);
+
         get_filesystem().write_rename_contents(
             lockfile_path(*this), "vcpkg-lock.json.tmp", Json::stringify(obj, {}), VCPKG_LINE_INFO);
     }