Techniques for location source ranking for determining device location are described. A location source generally refers to a source of position information (e.g., GPS coordinates, latitude and longitude, street addresses, and so forth) that can be used to determine a geographical location of a device. According to one or more embodiments, location sources and/or combinations of location sources can be ranked based on various criteria. Thus, when a location is requested for a particular device, a highest ranking available location source or combination of location sources can be selected to determine a location of the device. Location source rankings, for instance, can be maintained on a client device and/or via a remote location-related service. According to various embodiments, a location of a device can be determined to enable emergency assistance to be provided at the location.