Alamosaurus was a massive, herbivorous sauropod dinosaur that lived during the Late Cretaceous period, around 70 to 66 million years ago. Reaching lengths of up to 30 meters (98 feet) and weighing as much as 30 metric tons, it was one of the largest dinosaurs in North America. Alamosaurus had a long neck and tail, with column-like legs supporting its immense body, enabling it to browse high vegetation like conifers and other tall plants. Its fossils have been primarily discovered in the southwestern United States, particularly in Texas, New Mexico, and Utah, indicating it was well adapted to semi-arid environments. Alamosaurus was among the last surviving sauropods before the mass extinction at the end of the Cretaceous.