In 1986, believing that the asteroid was of S-type and that it had a diameter of 15 km, the length of 916 America's day was thought to be 38 hours. Observations by the Infrared Astronomical Satellite have since shown that it has a diameter of 33.2±1.3 km, with an absolute magnitude of 11.20 and an albedo (the extent to which it reflects light) of 0.053±0.004.