A system for locating a mobile wireless device is configured to communicate with a wireless communications system via a control plane and a user plane. The user plane includes a data channel, and the system includes a server configured to communicate via the data channel with a wireless device to be located. The server obtains from the wireless device information useful for tasking the wireless location system. The information useful for tasking may include information indicative of at least one cell site neighboring a serving cell site with which the wireless device is communicating. This may include information indicative of a serving cell site, a reverse channel through which the wireless device is communicating, and/or a hopping pattern, etc. The system may be used, for example, in connection with a GSM or UMTS wireless communications system.