San Antonio

San Antonio covers 477.8 acres in one piece and holds 464 addresses on 515 parcels, at a median lot of 0.384 acres. The zoning runs 242.3 acres Planned Development, 83.8 acres Residential Estate and 23.9 acres Residential Suburban, and 270 of the parcels sit in the city's planned development district 12 with a further 88 in district 11. Twenty-eight named streets run 7.66 miles inside the boundary and 86 of the 273 centerline segments are private. San Antonio Park sits on 10.6 acres at 4185 1/2 San Antonio Road with a playground, restrooms, barbecues and picnic tables, and the Casino Ridge Staging Area occupies a further acre at 21202 Casino Ridge Road, recorded by the city as equestrian staging.

Riding is the reason the trail furniture is there. The city's trail layer runs 2.37 miles inside the boundary, twelve segments of bare earth attributed to its landscape and maintenance district and one paved segment attributed to Chino Hills State Park, and the point layer records ten trail entry points, four dog bag dispensers, two water troughs and two hitching posts. The fire exposure is the largest in the city: the 2025 fire hazard severity layer rates 443.9 acres Very High, more than any other zone Yorba Linda draws, and 367 of the 464 addresses are flagged high fire severity with 199 carrying a fuel modification requirement. The state landslide zone layer covers 158.9 acres and an Alquist-Priolo earthquake fault zone 121.6 acres.

San Antonio Road carries the name Bernardo Yorba gave his own house. Mexican governor Jose Figueroa granted him Rancho Canon de Santa Ana in 1834, and on it he built the Hacienda de San Antonio, a two story adobe of ninety rooms with walls twenty six inches thick and a dance hall with a polished floor. It was the center of life in this canyon, a self contained town running on the families who worked the rancho, until he died in 1858.

The oil field under the southern half is called Esperanza, which is Spanish for hope, and the name was on this land long before the oil was. Prudencio Yorba, a son of Bernardo, called his ranch Esperanza for a daughter who had died just before he moved onto it. Eighteen wells sit inside this boundary and four of them are still active. San Antonio Park covers 10.6 acres with a playground and restrooms, and the Casino Ridge Staging Area gives riders somewhere to unload.