High Quality Content by WIKIPEDIA articles! Sierra Army Depot is a United States Army post located near the unincorporated city of Herlong, California 55 miles (89 km) northwest of Reno, NV and 40 miles (64 km) southeast of Susanville, CA. Sierra Army Depot is in the highest desert plain east of the Sierra Nevada mountains at an elevation of 4,200 feet (1,300 m). The high desert plain is only sparsely developed.