diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..25aa1c8
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,8 @@
+import { Feature, FeatureCollection, LineString } from 'geojson';
+
+declare function lineSliceAtIntersection(
+  line: Feature<LineString>,
+  segmenter: Feature,
+): FeatureCollection<LineString>;
+
+export { lineSliceAtIntersection as default };
diff --git a/package.json b/package.json
index 13983ea..471b159 100644
--- a/package.json
+++ b/package.json
@@ -30,6 +30,7 @@
     "xtend": "^4.0.1"
   },
   "devDependencies": {
+    "@types/geojson": "^7946.0.14",
     "dox": "^0.8.0",
     "doxme": "^1.8.2",
     "eslint": "^1.6.0",