diff --git a/HISTORY.md b/HISTORY.md
index ba0f4cb..883f32a 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,3 +1,8 @@
+unreleased
+==========
+
+  * Fix JSDoc for `Router` constructor
+
 1.3.2 / 2017-09-24
 ==================
 
diff --git a/index.js b/index.js
index e2369b5..8e79b94 100644
--- a/index.js
+++ b/index.js
@@ -48,7 +48,7 @@ module.exports.Route = Route
 /**
  * Initialize a new `Router` with the given `options`.
  *
- * @param {object} options
+ * @param {object} [options]
  * @return {Router} which is a callable function
  * @public
  */