Southern California

Lore & Background

Following the acquisition of the territory of California by the United States, several pro-slavery politicians attempted to arrange the division of Alta California at 36 degrees, 30 minutes, the line of the Missouri Compromise. Instead, the passing of the Compromise of 1850 enabled California to be admitted to the Union as a free state, preventing the southern half of California from becoming its own separate slave state. Subsequently, southern Californians dissatisfied with inequitable taxes and land laws attempted several times in the 1850s to achieve a separate statehood or territorial status separate from northern California.

The only successful proposal, the Pico Act of 1859, was passed by the California State Legislature and signed by State Governor John B. Weller. It was approved overwhelmingly by nearly 75 percent of southern California voters to form the proposed Territory of Colorado. The Pico Act bisected California starting at a latitude of six standard parallels south of the Mount Diablo meridian, then ducking southward around part of the Central Valley before cutting northeast to the California border.

Six standard parallels is 144 miles south of Mount Diablo—which corresponds to the current northern border of San Luis Obispo County, at the latitude 35°45'N. The proposal was sent to Washington, D.C., with a strong advocate in Senator Milton Latham. However, the secession crisis following the election of Abraham Lincoln in 1860 and the subsequent American Civil War led to the proposal never coming to a vote.

Reader's Guide

Southern California encompasses eight metropolitan areas (MSAs), three of which together form the Greater Los Angeles Combined Statistical Area (CSA) with over 18 million people, the second-biggest CSA after the New York CSA. These three MSAs are the Los Angeles metropolitan area (Los Angeles and Orange counties, with 13.3 million people), the Inland Empire (Riverside and San Bernardino counties, including the Coachella Valley cities, with 4.3 million people), and the Oxnard–Thousand Oaks–Ventura metropolitan area (0.8 million people).

In addition, Southern California contains the San Diego metropolitan area with 3.3 million people, Bakersfield metro area with 0.9 million, and the Santa Barbara, San Luis Obispo, and El Centro (Imperial County) metropolitan areas. The Southern California Megaregion (or megalopolis) is larger still, extending northeast into Las Vegas, Nevada and south across the Mexican border into Tijuana.

Did You Know?

• The Pico Act of 1859 was approved by nearly 75 percent of southern California voters, not 56% or 57.5%.
• Southern California has a population of 23.76 million residents as of the 2020 census.