The Spanish military expedition led by Ruiz was exploring inland routes to the San Joaquin Valley and 'upper' settled Alta California, via the deserts from colonial New Spain (present day Mexico).

The ancient native trail now known as Old Tejon Pass was "discovered" in 1772 by Spanish explorer Pedro Fages,[2] and used in 1776 by padre Francisco Garces, traveling east of the Anza Colonizing Expedition's main route.

[4] Williamson much preferred as a wagon route the lower and easier Grapevine Canyon to the west that led to a pass between the Tehachapi and San Emigdio Mountains.

There at the Sinks of Tejon, the creek's waters sank into the ground of the San Joaquin Valley here during the dry season, instead of reaching Kern Lake.

The California Historical Landmark reads: Source: "List of Butterfield Overland Mail Stations "Itinerary of the Route"" (PDF).