The area is connected to the internal NTS road network, with paved roads leading both to Mercury, to the northwest, and west to Yucca Flats. Leading northeast from the lake, Groom Lake Road (a wide, well-conditioned dirt road) runs through a pass in the Jumbled Hills. Groom Lake Road was formerly the track leading to mines in the Groom basin, but has been improved since their closure. Its winding course takes it past a security checkpoint, but the restricted area around the base extends further east than this (unauthorized visitors who travel west on Groom Lake Road are usually observed first by guards located on the hills surrounding the pass, still several miles from the checkpoint). After leaving the restricted area (marked by numerous warning signs stating that "photography is prohibited" and that "use of deadly force is authorized" under the terms of the 1950 McCarran Internal Security Act) Groom Lake Road descends eastward to the floor of the Tikaboo Valley, passing the dirt-road entrances to several small ranches, before joining with Nevada State Route 375, the "Extraterrestrial Highway", south of Rachel.