A service is described that discovers the physical locations of a computer's connections to logical networks and provides that information to applications. The service decides which method or methods for discovering physical location information are applicable to each network interface on the computer, applies those methods, and collects the results. The results are then converted into a common format. In addition to physical location, the information may include estimates of the quality and reliability of the information, such as error ranges and confidence intervals, and the methods used to gather the information. The information is made available to whatever system services and applications need it. Clients of the physical location information may be notified when the information provided to them changes or when new information becomes available. Clients may specify a threshold so that location changes of a magnitude below the threshold are not reported to them.