In the last decades of the nineteenth
century, a few cattlemen began driving their herds down to the
Borrego Valley for winter grazing. Among the first were the Helm
brothers, who settled in the Warner Ranch/Montezuma Valley area
in the late 1860s and early 1870s. They came to regard the
valley as their own private domain, and in 1872 are said to have
run off a French sheepherder named Bosque, who dared to
establish a sheep camp at the spring in the lower end of the
valley.
By the early 1880s that spring was known
as Borrego Spring. The name— spelled Borego—first appears on a
county map in 1883. It is a misspelling of the Spanish word
borrego which means a yearling lamb. Colloquially it also means
a simpleton, or a fool. It has long been assumed that the spring
was named because of the Desert Bighorn sheep that once watered
there, but the term borrego refers to domestic, not wild sheep.
More likely then, Borrego Spring was named because of the
sheepherders (not necessarily Bosque alone) who watered their
flocks there in the late 19th Century.
Source:
https://www.sandiegohistory.org/journal/97winter/borrego.htm
