1. A computer-implemented method comprising: obtaining a first DNS query from a client computing device at a first DNS server, wherein the first DNS query corresponds to a first requested resource and wherein the first DNS server corresponds to a content delivery network service; obtaining a query IP address associated with the first DNS query at the first DNS server, wherein the query IP address is associated with the client computing device; obtaining, at the first DNS server from a routing data store, a location-based identifier at least based on a portion of the obtained query IP address, wherein the routing data store includes IP address to location-based identifier mappings, and wherein individual IP address to location-based identifier mappings have a corresponding confidence factor; and resolving the first DNS query based on the location-based identifier.