1. An apparatus comprising: a memory device to store an index system that identifies sub-polygons in a region of interest; and a processor and non-volatile memory comprising a set of computer-readable instructions, wherein the processor is configured the computer readable instructions to: process a location query received from a client device, wherein the location query includes a location identifier associated with the client device's location; determine a query identifier corresponding to the location identifier; compare one or more bits in the query identifier with bits in the index system to determine that the query identifier is represented in the index system and that the location identifier provided by the client device is within the region of interest; compare a first set of bits of the query identifier, corresponding to a lower-precision sub-polygon, to the index system; compare a second set of bits of the query identifier, corresponding to a higher-precision sub-polygon, to the index system; and provide a service associated with the region of interest to the client device over a communication network after determining that the location identifier provided by the client device is within the region of interest.