Antelope Valley is located in northern Los Angeles County, California and the southeast portion of Kern County, California, and constitutes the western tip of the Mojave Desert. It is situated between the Tehachapi and the San Gabriel Mountains. The valley was named for the pronghorns that are said to have roamed there until being eliminated by hunters and bad weather in the 1880s. The principal cities in the Antelope Valley are Palmdale and Lancaster. Edwards Air Force Base lies east of Rosamond, U. S. Air Force Plant 42 in northeast Palmdale is home to Lockheed Martin, Boeing, Northrop Grumman, and BAE Systems, among other aerospace-related companies. The Valley has a choice of transportation from airports to mass transit and freeways.