724 Hapag is a minor planet orbiting the Sun in the asteroid belt that was found by Austrian astronomer Johann Palisa in 1911 and named after the German shipping company Hamburg America Line. It was assigned a provisional name of 1911 NC, then became a lost asteroid until it was rediscovered in 1988 as by Tsutomu Hioki and N. Kawasato at Okutama, Japan. Photometric observations of this asteroid at the Organ Mesa Observatory in Las Cruces, New Mexico in 2011 gave a light curve with a period of 3.1305 ± 0.0001 hours and a brightness variation of 0.11 ± 0.01 in magnitude.