Rancho Santa Margarita is an affluent city in Orange County, California. One of Orange County's youngest cities, Rancho Santa Margarita is a master planned community set upon rolling hills. Most neighborhoods in Rancho Santa Margarita are within various homeowners associations. The population was 47,853 at the 2010 census, up from 47,214 at the 2000 census.

Rancho Santa Margarita, CA