Abstract: The present concepts relate to interpolating a location of an address. In one example, an address index may be generated, which contains rooftop addresses and corresponding percentage values representing the percentage distances along street primitives at which those rooftop addresses are located based on rooftop locations of the rooftop addresses. Upon receiving a query address, whose rooftop location is not known, the address index can be referenced to identify two surrounding rooftop addresses between which the query address lies, and an estimated geographical location of the query address may be calculated by interpolating between the rooftop locations of the two surrounding rooftop addresses.