This specification describes technologies relating to aligning content items with map features. In general, one aspect of the subject matter described in this specification can be embodied in methods that include receiving a request for an online map and selecting a shape in the online map to accommodate overlay of a content item. The methods may further include scaling a content item to fit the shape and aligning the content item with an edge of the shape. The methods may further include rendering the map with the content item projected onto the shape and transmitting data encoding the rendered map in response to the request.