1. A method comprising: receiving, at a computing device, a plurality of location identifiers corresponding to a plurality of locations at which a mobile computing device was previously located; defining, by the computing device, a plurality of geographic regions based at least in part on the plurality of location identifiers, wherein at least one of the plurality of locations is located in each of the plurality of geographic regions; selecting, by the computing device, a subset of the plurality of geographic regions based on respective distances between a current location of the mobile computing device and a respective reference point within each of the geographic regions, wherein selecting the subset of the plurality of geographic regions comprises selecting one or more smaller geographic regions for short distances between the current location and respective reference points of the plurality of geographic regions and selecting one or more larger geographic regions for long distances between the current location and respective reference points of the plurality of geographic regions, the one or more smaller geographic regions being smaller than the one or more larger geographic regions; and outputting, by the computing device and for display, an indication of the subset of the plurality of geographic regions.