Methods, systems, and apparatus, including computer programs encoded on computer storage media, for determining geographic locations. One of the methods includes obtaining a sequence of events, each of the events including geographical location information, from a first device to be located; determining, for each event and each of a plurality of geographical locations, a probability that the respective event was obtained from a second device given that the second device is located at the respective geographical location; determining a probability that the sequence of events was obtained from the second device, including using a model representing how sequences of events are generated by network devices; and determining for each of the plurality of geographical locations a probability that the first device is located at the respective geographical location using the probability that the sequence of events was obtained.