diff --git a/externs/geojson.js b/externs/geojson.js
new file mode 100644
index 0000000000..68a6bc0178
--- /dev/null
+++ b/externs/geojson.js
@@ -0,0 +1,105 @@
+/**
+ * @fileoverview Externs for GeoJSON.
+ * @see http://geojson.org/geojson-spec.html
+ * @externs
+ */
+
+
+
+/**
+ * @constructor
+ */
+var GeoJSONCRS = function() {};
+
+
+/**
+ * @type {string}
+ */
+GeoJSONCRS.prototype.type;
+
+
+/**
+ * @type {!Object.<string, *>}
+ */
+GeoJSONCRS.prototype.properties;
+
+
+
+/**
+ * @constructor
+ */
+var GeoJSONGeometry = function() {};
+
+
+/**
+ * @type {string}
+ */
+GeoJSONGeometry.prototype.type;
+
+
+/**
+ * @type {!Array.<number>|!Array.<!Array.<number>>}
+ */
+GeoJSONGeometry.prototype.coordinates;
+
+
+
+/**
+ * @constructor
+ */
+var GeoJSONFeature = function() {};
+
+
+/**
+ * @type {string}
+ */
+GeoJSONFeature.prototype.type;
+
+
+/**
+ * @type {GeoJSONGeometry}
+ */
+GeoJSONFeature.prototype.geometry;
+
+
+/**
+ * @type {Object.<string, *>}
+ */
+GeoJSONFeature.prototype.properties;
+
+
+
+/**
+ * @constructor
+ */
+var GeoJSONFeatureCollection = function() {};
+
+
+/**
+ * @type {string}
+ */
+GeoJSONFeatureCollection.prototype.type;
+
+
+/**
+ * @type {!Array.<GeoJSONFeature>}
+ */
+GeoJSONFeatureCollection.prototype.features;
+
+
+/**
+ * @type {!Array.<number>|undefined}
+ */
+GeoJSONFeatureCollection.prototype.bbox;
+
+
+/**
+ * @type {!GeoJSONCRS|undefined}
+ */
+GeoJSONFeatureCollection.prototype.crs;
+
+
+/**
+ * @type {!Object.<string, *>}
+ */
+GeoJSONFeatureCollection.prototype.properties;
diff --git a/main.json b/main.json
index 16f03d34e8..6177730616 100644
--- a/main.json
+++ b/main.json
@@ -11,6 +11,10 @@
     "goog.DEBUG": false
   },
 
+  "externs": [
+    "externs/geojson.js"
+  ],
+
   "mode": "ADVANCED",
   "level": "VERBOSE",
   "pretty-print": true,