Baseline and Meridian
On November 7, 1852, Colonel Henry Washington, a deputy surveyor, surveyed the San Bernardino Base Line and Meridian from a point west of Mount San Bernardino (10,649 feet/3,246 meters). The base and meridian lines serve as the initial surveying point for all of Southern California. The lines cross at latitude 34.12134 and longitude -117.34859.
Because of the state's shape, three meridian-base line sets are required for surveys in all parts of the state. The other two are the Mount Diablo and Humbolt base and meridian lines.
Update 1: This photo was used to accompany an article by Beth Kanter, What's Your Social Media Baseline?, on March 7, 2009.
Update 2: This photo and a small quote appeared in an article, I Always Wondered About This, on Ron's Log on June 19, 2009.