1. A computer-implemented method comprising: generating a set of address-to-location mappings by performing the following steps for each of a plurality of network addresses: receiving information about a plurality of location-known requests that originated from one or more requesting devices, wherein, when each location-known request of the plurality of location-known requests was sent, the requesting device that sent the location-known request was uniquely identified by a network address, wherein the information indicates a plurality of distinct locations associated with the network address, identifying a geographical area based, at least in part, on the plurality of distinct locations, mapping the geographical area to at least one geographical locality, and generating an address-to-location mapping that associates the network address with the at least one geographical locality; and generating a plurality of address-range-to-location mappings by combining address-to-location mappings, from the set of address-to-location mappings, based on: addresses specified in the address-to-location mappings, and locations specified in the address-to-location mappings.