San Diego County became one of California’s original 27 counties on Feb. 18, 1850, shortly after California became the 31st state in the Union.

San Diego County covers 4,526 square miles, an area approximately the size of the state of Connecticut, extending 70 miles along the Pacific coast from Mexico to Orange County and inland 75 miles to Imperial County along the international border with Mexico.

San Diego County enjoys a wide variety of climate and terrain, from coastal plains and fertile inland valleys to mountain ranges and the Anza-Borrego Desert in the east. The Cleveland National Forest occupies much of the interior portion of the county. The climate is temperate in the coastal and valley regions, where most resources and population are located. The average annual rainfall is only 10 inches for the coastal regions, so the county is highly reliant on imported water.