Rancho Santa Margarita is a city in Orange County, California, United States. One of Orange County’s youngest cities, Rancho Santa Margarita is a master planned community set upon rolling hills. The majority of the neighborhoods in RSM are maintained by larger homeowners associations including SAMLARC, Melinda Heights, town center, Dove Canyon, Rancho Cielo, Robinson Ranch, and Trabuco Highlands. SAMLARC, Dove Canyon, Trabuco Highlands, Robinson Ranch, and Rancho Cielo were all established before Rancho Santa Margarita was an incorporated community. East of Plano Trabuco Road is designated with a Trabuco Canyon (92679) zip code even though the area falls within the City of Rancho Santa Margarita boundary.