From the Orange County (Calif.) Weekly, a story about how drought shaped Southern California:

Orange County as we know it exists because of the Great Drought of 1864. It wrecked Southern California’s cattle industry, then one of the largest in the world and the heart of the area’s economy, and forced ranchers to unload their land at fire-sale rates. Developers swooped in and divided their newly acquired properties into lots that evolved into the cities of today. Those settlements, in turn, drew in Americans who pushed out the state’s original Californio families. Enough people came to make Orange County’s secession from Los Angeles County in 1889 a natural. And those residents transformed pastoral OC into a suburban paradise that brought us national acclaim–and also sowed the seeds for our current water crisis.