diff --git a/common/api/core-frontend.api.md b/common/api/core-frontend.api.md
index dffec0186414..daf63d155505 100644
--- a/common/api/core-frontend.api.md
+++ b/common/api/core-frontend.api.md
@@ -5799,13 +5799,9 @@ export enum MapLayerImageryProviderStatus {
 
 // @beta
 export interface MapLayerOptions {
-    // (undocumented)
     [format: string]: MapLayerKey | undefined;
-    // (undocumented)
     AzureMaps?: MapLayerKey;
-    // (undocumented)
     BingMaps?: MapLayerKey;
-    // (undocumented)
     MapboxImagery?: MapLayerKey;
 }
 
diff --git a/common/changes/@itwin/core-frontend/geo-doc_MapLayerOptions_2022-04-07-18-09.json b/common/changes/@itwin/core-frontend/geo-doc_MapLayerOptions_2022-04-07-18-09.json
new file mode 100644
index 000000000000..04fe6329fb95
--- /dev/null
+++ b/common/changes/@itwin/core-frontend/geo-doc_MapLayerOptions_2022-04-07-18-09.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@itwin/core-frontend",
+      "comment": "Added documentation for MapLayerKey.",
+      "type": "none"
+    }
+  ],
+  "packageName": "@itwin/core-frontend"
+}
\ No newline at end of file
diff --git a/core/frontend/src/tile/map/MapLayerFormatRegistry.ts b/core/frontend/src/tile/map/MapLayerFormatRegistry.ts
index b1c4936b58a4..1d0f763d0fdd 100644
--- a/core/frontend/src/tile/map/MapLayerFormatRegistry.ts
+++ b/core/frontend/src/tile/map/MapLayerFormatRegistry.ts
@@ -36,16 +36,20 @@ export interface MapLayerSourceValidation {
 }
 
 /**
- * Options to be passed to the IModelApp on startup which contain access keys for various layer formats
+ * Options supplied at startup via [[IModelAppOptions.mapLayerOptions]] to specify access keys for various map layer formats.
  * @beta
  */
 export interface MapLayerOptions {
+  /** Access key for Azure Maps in the format `{ key: "subscription-key", value: "your-azure-maps-key" }`. */
   // eslint-disable-next-line @typescript-eslint/naming-convention
   AzureMaps?: MapLayerKey;
+  /** Access key for Mapbox in the format `{ key: "access_token", value: "your-mapbox-key" }`. */
   // eslint-disable-next-line @typescript-eslint/naming-convention
   MapboxImagery?: MapLayerKey;
+  /** Access key for Bing Maps in the format `{ key: "key", value: "your-bing-maps-key" }`. */
   // eslint-disable-next-line @typescript-eslint/naming-convention
   BingMaps?: MapLayerKey;
+  /** Access keys for additional map layer formats. */
   [format: string]: MapLayerKey | undefined;
 }