The Utah Test and Training Range (UTTR) is a military testing and training area located in Utah's West Desert, approximately 80 miles (130 km) west of Salt Lake City, Utah. UTTR is currently the largest overland contiguous block of supersonic authorized restricted airspace in the contiguous United States. The range, which has a footprint of 2,675 square miles (6,930 km2) of ground space and over 19,000 square miles (49,000 km2) of air space, is divided into North and South ranges. Interstate 80 divides the two sections of the range. The site is administered and maintained by the US Air Force's HQ UTTR, formerly known as the 388th Range Squadron (388RANS) stationed at Hill Air Force Base, Utah.