To entice the Southern Pacific Railroad to build a railhead near his cattle ranch, Santa Margarita Ranch owner Patrick Murphy gave easements across his land and 640 acres to the Southern Pacific land development company, The Pacific Improvement Company, to build the Town of Santa Margarita. On April 24, 1889 a Grand Auction was held to sell the lots.

Streets in towns developed by the railroad were assigned letters instead of numbers. The SP Railroad numbered its tracks and used letters for the street names that ran parallel to the tracks to eliminate confusion. The railroad towns of San Miguel and Lompoc also have lettered streets.

Why the first street in town isn’t called ‘A’ Street. It was on an 1889 map. ‘A’ Street began at the Santa Margarita Ranch Headquarters and continued to M Street on the eastside of town. The L.D. Norton (Surveyor) 1889 maps show streets that were not developed (A-E and L-N). This map was not recorded with the Clerk Recorders Office as most maps at the time weren’t. A subsequent map in 1902 didn’t show the missing streets.