diff --git a/include/geo/point_rtree.h b/include/geo/point_rtree.h
index 3ce4d71..351f011 100644
--- a/include/geo/point_rtree.h
+++ b/include/geo/point_rtree.h
@@ -37,6 +37,8 @@ struct point_rtree {
 
   std::vector<size_t> within(geo::box const&) const;
 
+  std::size_t size() const;
+
 private:
   struct impl;
   std::unique_ptr<impl> impl_;
diff --git a/src/point_rtree.cc b/src/point_rtree.cc
index 15a4f94..b5d172d 100644
--- a/src/point_rtree.cc
+++ b/src/point_rtree.cc
@@ -77,6 +77,8 @@ struct point_rtree::impl {
     return results;
   }
 
+  std::size_t size() const { return rtree_.size(); }
+
   rtree_t rtree_;
 };
 
@@ -119,4 +121,6 @@ std::vector<std::pair<double, size_t>> point_rtree::nearest(
   return impl_->nearest(center, k);
 }
 
+std::size_t point_rtree::size() const { return impl_->size(); }
+
 }  // namespace geo