diff --git a/types/atom/index.d.ts b/types/atom/index.d.ts
index 9b0d194976..925061ed63 100644
--- a/types/atom/index.d.ts
+++ b/types/atom/index.d.ts
@@ -949,6 +949,9 @@ export interface Marker {
 
 /** Experimental: A container for a related set of markers. */
 export interface MarkerLayer {
+    /** The identifier for this MarkerLayer. */
+    id: string;
+
     // Lifecycle
     /** Create a copy of this layer with markers in the same state and locations. */
     copy(): MarkerLayer;