Bitter Spring (San Bernardino County)

Bitter Spring is a spring within the Fort Irwin National Training Center in San Bernardino County, California. It lies at an elevation of 1355 feet and is located in a valley between the Soda Mountains to the east, the Tiefort Mountains to the northwest, Alvord Mountain to the southwest and Cronese Mountains to the south and southeast.

Bitter Spring was a water and food source for the Native American peoples that lived in this part of the desert. It became a watering and grazing place between Salt Spring and the Mojave River on the Old Spanish Trail. It passed 38.75 miles south through Silurian Valley, then east through the Avawatz Mountains at Red Pass and beyond the playa of Red Pass Lake, through a gap between the Soda and Tiefort Mountains to Bitter Spring in a wash in the next valley. From Bitter Spring the trail led 18.75 miles southwest climbing Alvord Mountain to cross Impassable Pass to descend Spanish Canyon and cross the plains to the location of Fork of the Road on the north side of the Mojave River where it met the Mohave Trail, that had become another branch of the Old Spanish Trail, often called the Main Branch that later became a wagon road called Government Road or Mojave Road.

From 1847, the Old Spanish Trail became a wagon road, later called the Mormon Road pioneered by a party of Mormons led by Jefferson Hunt that first traveled back and forth on it in 1847-1848. From 1849 it became known by the Forty-Niners as the "Southern Route", of the California Trail, the winter route of the Forty-niners, Mormons, and other immigrants to California. From 1855 after the route was modified and improvements made by the State of California in Cajon Pass and by the Federal government in Utah Territory, it became the winter trade route and wagon road between Utah Territory and California, it was known as the Los Angeles - Salt Lake Road.

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