Mountain Pass is an unincorporated community in San Bernardino County, California, United States. It is situated on Interstate 15 in the southeast mountainous desert region of the state approximately 15 miles (24 km) from the Nevada border at an elevation of 4,730 feet (1,440 m) - the highest point along I-15 between California and Nevada. It has a population of 30.
The most prominent feature of the town, and its reason for existence, is the Mountain Pass rare earth mine, an open pit mine forrare earth elements. The mine and its associated processing facilities, which are owned by Molycorp Minerals, are currently undergoing expansion and modernization, and returned to production in 2013. In 2015, Molycorp declared bankruptcy and the mine closed its doors again.