Mojave Trails National Monument is a vast, largely undeveloped protected desert landscape in California, between Interstates 15 and 40 and partly surrounding Mojave National Preserve. Designated in 2016 and managed by the Bureau of Land Management, it is the largest national monument in the contiguous United States. Its mountain ranges, volcanic landforms, dunes, and open basins preserve the scale and isolation of the Mojave, while wilderness areas, Bonanza Spring, Amboy Crater, and Afton Canyon stand out among its features. It also protects major historic corridors, including the Old Spanish Trail, Route 66, and remnants of the World War II-era Desert Training Center.