Methods, program products, and systems of using a mobile WAP for location and context purposes are disclosed. In general, in one aspect, a server can estimate an effective location of a wireless access gateway using harvested data. The server can harvest location data from multiple mobile devices. The harvested data can include a location of each mobile device and an identifier of a wireless access gateway that is located within a communication range of the mobile device. In some implementations, the server can identify a mobile wireless access gateway based on a distance comparison. Data indicating the mobility of a wireless access gateway can be used by a mobile device to initiate one or more actions, including managing power of the mobile device, modifying entrance and exit conditions of virtual fences and determining a context of the mobile device.