Mountain Pass is an unincorporated community in San Bernardino County, California, United States.

The mine and its associated processing facilities are owned by MP Materials, which purchased the assets out of bankruptcy on July 10, 2017.

[3] Typical of the High Desert, Mountain Pass has a cold semi-arid climate (Köppen climate classification BSk), Winters are chilly but also sunny, with daytime highs around 50 and nighttime lows just below freezing.

Summers are hot and somewhat wetter, with July, the hottest month, having a normal high in the low 90s.

Most of the snow doesn't stick to the ground very long, usually melting by mid afternoon.