Google added Polylines and Polygons to Maps API v3. These allow you to draw lines or filled regions on the map, specify stroke and fill styles, and handle events, and work in all supported browsers. Also made a few improvements from Polylines and Polygons in Maps API v2. You can send in multiple paths for one Polygon, and use that to render holes inside your poly. When you give us a set of vertices, Goolge assign a level of detail to each vertex, showing only the necessary amount of vertices per zoom level. Adding a polyline or polygon to a map is easy, read the documentation.