Brachiosaurus (/ˌbrækiəˈsɔːrəs/) is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154–150 million years ago. Brachiosaurus is estimated to have been between 18 and 21 meters (59 and 69 ft) long; weight estimates range from 28.3 to 58 metric tons (31.2 and 64 short tons).