California State Route 14 is a north-south highway largely in the Mojave Desert, also known as the High Desert, just east of the crest of the Sierra Nevada in its northern part. It connects U.S. Highway 395 in eastern California (no town is close to the intersection) to Interstate 5 in Santa Clarita, California . With US 395 it connects the western part of greater Los Angeles with such places as Reno, Nevada. While its southern part runs through the suburbanized and rural canyon areas that can have heavy commuter traffic, its northern section generally affords an attractive, stark view of the Sierra Nevada. It is in mostly desert terrain, so those who travel it should make the appropriate precautions for travel upon it, especially in the thinly-settled portions north of Mojave during the hot summers.

Route 14, all of it since re-routed to the Antelope Valley Freeway south of the community of Mojave, is the designation for old U.S. Highway 6 between US 395 and Interstate 5 after California truncated US 6 at Bishop, California in 1964. The old surface road south of and in Mojave is still known as the Sierra Highway. North of Mojave the road is known as the Midland Trail.As part of the former transcontinental US 6, non-freeway segments are also known as the Grand Army of the Republic Highway.

It passes through Palmdale, Lancaster, and Rosamond, all of which have grown rapidly beginning in 1983. It is co-routed with California State Highway 138 from Palmdale Boulevard (138 East) in Palmdale to Avenue D (138 West) north of downtown Lancaster. The route also intersects with the new California State Highway 58 bypass north of downtown Mojave, as well as California State Highway 178 's west and east legs north of Red Rock Canyon.