Castle Mountains National Monument is a U.S. National Monument located in the eastern Mojave Desert and northeastern San Bernardino County, in the state of California.

[1][2][3] The park protects 20,920 acres, located between the interstates I−15 and I−40, and northwest of the Colorado River.

The range lies south and east of the New York Mountains, southwest of Searchlight and west of Cal-Nev-Ari, Nevada.

The range lies at the northeastern end of Lanfair Valley and reaches 5,543 feet (1,690 m) in elevation at the summit of Hart Peak and 5580 ft at Linder Peak.

It surrounds the Castle Mountain Mine Area, an open pit gold mine in the southern Castle Mountains owned by Canadian NewCastle Gold Ltd., who can excavate nearly 10 million tons of ore through 2025, though due to low gold prices mining has been suspended since 2001.