Many third parties desire to discover and disclose your location with the help of your cell phone. Using an embedded GPS, phone software will commonly reveal coordinates to carriers, advertisers, and applications. Can a remote party determine locational information absent explicit GPS information? For example, given a known starting or ending point, can a streaming music server distinguish the path you’ve taken through the physical world? We show that the path a cell phone and its owner take from or to a known location can be determined from remote observations of changes in TCP throughput. Empirically, our method can correctly determine with greater than 78% accuracy the path taken by phone from one of four paths, and with 63% accuracy the path taken from among eight paths.