diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Locations/NonGeneratedSourceLocation.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Locations/NonGeneratedSourceLocation.cs
index 69e9ea4e9dc7..7a13138ff6ac 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Locations/NonGeneratedSourceLocation.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Locations/NonGeneratedSourceLocation.cs
@@ -40,8 +40,29 @@ public File FileEntity
             get;
         }
 
+        private static void WriteStarId(EscapingTextWriter writer)
+        {
+            writer.Write('*');
+        }
+
+        public sealed override void WriteQuotedId(EscapingTextWriter writer)
+        {
+            if (Context.ExtractionContext.IsStandalone)
+            {
+                WriteStarId(writer);
+                return;
+            }
+            base.WriteQuotedId(writer);
+        }
+
         public override void WriteId(EscapingTextWriter trapFile)
         {
+            if (Context.ExtractionContext.IsStandalone)
+            {
+                WriteStarId(trapFile);
+                return;
+            }
+
             trapFile.Write("loc,");
             trapFile.WriteSubId(FileEntity);
             trapFile.Write(',');
diff --git a/csharp/ql/lib/change-notes/2025-10-10-starid-locations.md b/csharp/ql/lib/change-notes/2025-10-10-starid-locations.md
new file mode 100644
index 000000000000..a258abcf3ab7
--- /dev/null
+++ b/csharp/ql/lib/change-notes/2025-10-10-starid-locations.md
@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* The extraction of location information for source code entities has been updated to use star IDs (`*` IDs). This change should be transparent to end-users but may improve extraction performance in some cases by reducing TRAP file size and eliminating overhead from location de-duplication.