Rossmoor is an affluent planned census-designated place located in Orange County, California. As of the 2010 census, the CDP had a total population of 10,244, down from 10,298 at the 2000 census. The gated Leisure World retirement community in the city of Seal Beach is to the south of Rossmoor, Los Alamitos is to the east and north, and Long Beach is to the west (on the other side of the San Gabriel River, the 605 freeway and the border with Los Angeles County). The community of Rossmoor has two shopping centers within its boundaries, but only one—the Rossmoor Village Square—is now within the political boundaries of the Rossmoor Community Services District. A larger shopping center, the Rossmoor Business Center, now remodeled and called the Shops at Rossmoor—was annexed, despite many protests, by the city of Seal Beach in 1962.
The Rossmoor community was developed from 1955 through 1961 by Ross W. Cortese, who had earlier developed the architecturally-significant Lakewood Rancho Estates in Long Beach (1953) and the Frematic Homes (1954) in Anaheim, just north and west of Disneyland. Originally created as a nudist colony, this quickly changed when Cortese's original partners in securing the first large parcels of land that would become Rossmoor included California governor Goodwin Knight and Judge Alfred Gittelson, who had also partnered with him in the Lakewood Rancho Estates and the Frematic homes. (It was Gittelson who later agreed to annex his Rossmoor Shopping Center property to Seal Beach in the 1960s.) After Rossmoor, Cortese would construct the first of his very successful Leisure World gated retirement community in that part of Seal Beach which is immediately south of Rossmoor. The Rossmoor community is easy to recognize because of its red brick "signature wall" that borders the entire unincorporated community. It is a signature of the Rossmoor community that differentiates it from neighboring cities Los Alamitos and Seal Beach.
There are 3,430 single family homes and 1 condominium complex within Rossmoor.