Reliable detectors for locating the position of a focal spot of visible radiation have been commercially available, but comparable infrared position sensors have not. This paper describes the development of two new detectors for infrared position sensing: (1) a room-temperature PbSe sensor, and (2) a liquid-nitrogen-cooled InSb sensor. With suitable electronics signal processing, each of these large sensor elements shows a linear response with x-and y-position displacement in the central region of the detector. These sensors are superior to previously reported detectors in threshold sensitivity, temporal frequency bandwidth, and drift. Detector characteristics and applications are discussed.