diff --git a/src/algorithms/superviewport.ts b/src/algorithms/superviewport.ts
index 0f3b6c77..706b5caa 100644
--- a/src/algorithms/superviewport.ts
+++ b/src/algorithms/superviewport.ts
@@ -29,7 +29,9 @@ import equal from "fast-deep-equal";
 
 export interface SuperClusterViewportOptions
   extends SuperClusterOptions,
-    ViewportAlgorithmOptions {}
+    ViewportAlgorithmOptions {
+  radius?: number;
+}
 
 export interface SuperClusterViewportState {
   /* The current zoom level */