The Utah Test and Training Range (UTTR) is a military testing and training area located in Utah's West Desert, approximately west of Salt Lake City, Utah. UTTR is currently the largest overland contiguous block of supersonic authorized restricted airspace in the continental United States. The range, which has a footprint of of ground space and over of air space, is divided into North and South ranges. I-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.