Yucca Mountain. Yucca Mountain is a mountain in Nevada, near its border with California, approximately 100 miles (160 km) northwest of Las Vegas. Located in the Great Basin, Yucca Mountain is east of the Amargosa Desert, south of the Nevada Test and Training Range and in the Nevada National Security Site. It is the site of the Yucca Mountain nuclear waste repository, which is currently identified by Congressional law as the nation's spent nuclear waste storage facility.