Hidden Hills

Hidden Hills covers 381.5 acres in one piece and holds 243 addresses on 276 parcels. Its median lot of 0.588 acres is the largest of the twenty-seven residential zones the city draws, and the zoning layer gives 309.7 acres to Residential Estate and 46.9 acres to Open Space Ranchette with nothing else in between. The assessor land use code marks 257 parcels here residential across 271.1 acres. Sixteen named streets run 4.85 miles inside the boundary, all of them public, and Hidden Hills Road alone accounts for 1.89 of those miles. Placentia-Yorba Linda Unified serves the whole polygon, and 0.98 miles of earthen multipurpose trail run inside it on segments the city attributes to its landscape and maintenance district.

The ground is steep and the city's hazard record says so plainly. The 2025 fire hazard severity layer rates 366.7 acres Very High, the second largest Very High area of any zone in the city, and all 243 addresses are flagged high fire severity with 200 of them carrying a fuel modification requirement. The state landslide zone layer covers 150 acres inside the boundary and an Alquist-Priolo earthquake fault zone crosses 78 acres. The flood layer keeps all 381.5 acres in zone X. The city records no park inside the boundary and 3.8 acres of it fall inside Chino Hills State Park.

Hidden Hills is 243 homes spread over 381 acres, with a median lot near six tenths of an acre, which makes it one of the most thinly settled pieces of Yorba Linda outside the working ranches. That is not an accident of planning so much as an inheritance: one of the three plugged wells recorded inside the boundary carries the Bryant Estate lease name, and this ground came off the ranch John Bixby bought from Bernardo Yorba's widow in 1875 and named Rancho Santa Ana. His daughter Susanna Bixby Bryant inherited it after his death in 1891.

The streets borrow from the hillside suburbs of Los Angeles. Brentwood Place, Westwood Lane, Mission Hills Lane and Rolling Hills Lane are all real communities on the other side of the county line, and Hidden Hills itself is a gated horse town in the western San Fernando Valley. Around them, Sky Ridge Drive, Skyline Drive, Starlight Drive, Starwood Drive, Green Crest Drive, Green Mount Place, High Tree Circle and Sunbeam Lane keep the elevation in view.