Estimating a location of a device at a particular point of time may incorporate one, two, or more different location data points. The location data points may be derived from communications networks, where there may be different mechanisms for determining location. As part of the location estimation, each cellular location in a cellular network may have a different error range associated with each cell, for example. The error range for each cell may be generated by collecting precise location data from Global Positioning System or other mechanism with high accuracy, and comparing that data to location data gathered from other sources. A database of error ranges for each cell and each location mechanism may be gathered and used to estimate the actual location of a device for a given time period.