diff --git a/.changeset/pretty-trainers-rescue.md b/.changeset/pretty-trainers-rescue.md
new file mode 100644
index 00000000000..967710d7d0f
--- /dev/null
+++ b/.changeset/pretty-trainers-rescue.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+`Trie<out A>` type annotations have been aligned. The type parameter was made covariant because the structure is immutable.
diff --git a/packages/effect/src/Trie.ts b/packages/effect/src/Trie.ts
index 0033d02246c..2e8c19984c4 100644
--- a/packages/effect/src/Trie.ts
+++ b/packages/effect/src/Trie.ts
@@ -34,7 +34,7 @@ export type TypeId = typeof TypeId
  * @since 2.0.0
  * @category models
  */
-export interface Trie<in out Value> extends Iterable<[string, Value]>, Equal, Pipeable, Inspectable {
+export interface Trie<out Value> extends Iterable<[string, Value]>, Equal, Pipeable, Inspectable {
   readonly [TypeId]: {
     readonly _Value: Covariant<Value>
   }
@@ -122,8 +122,8 @@ export const make: <Entries extends Array<readonly [string, any]>>(
  * @category mutations
  */
 export const insert: {
-  <V>(key: string, value: V): (self: Trie<V>) => Trie<V>
-  <V>(self: Trie<V>, key: string, value: V): Trie<V>
+  <V1>(key: string, value: V1): <V>(self: Trie<V>) => Trie<V | V1>
+  <V1, V>(self: Trie<V>, key: string, value: V1): Trie<V | V1>
 } = TR.insert
 
 /**
@@ -746,8 +746,8 @@ export const forEach: {
  * @category mutations
  */
 export const modify: {
-  <V>(key: string, f: (v: V) => V): (self: Trie<V>) => Trie<V>
-  <V>(self: Trie<V>, key: string, f: (v: V) => V): Trie<V>
+  <V1, V>(key: string, f: (v: V) => V1): (self: Trie<V>) => Trie<V1 | V>
+  <V1, V>(self: Trie<V>, key: string, f: (v: V) => V1): Trie<V | V1>
 } = TR.modify
 
 /**
@@ -807,6 +807,6 @@ export const removeMany: {
  * @category mutations
  */
 export const insertMany: {
-  <V>(iter: Iterable<[string, V]>): (self: Trie<V>) => Trie<V>
-  <V>(self: Trie<V>, iter: Iterable<[string, V]>): Trie<V>
+  <V1>(iter: Iterable<[string, V1]>): <V>(self: Trie<V>) => Trie<V | V1>
+  <V1, V>(self: Trie<V>, iter: Iterable<[string, V1]>): Trie<V | V1>
 } = TR.insertMany