Siena

Siena covers 33.6 acres and holds 126 addresses on 149 parcels, at a median lot of 0.195 acres. Two streets serve the whole community, Siena and Pienza Street, 0.86 miles between them. The city's zoning layer gives 28 acres to Attached Residential District, with 4.4 acres of street and 0.9 acres zoned park and recreation. The boundary sits inside a hole cut in the Marina Hills polygon, and Siena names Marina Hills Planned Community Association as its master.

The city's HOA zoning lookup records Siena as gated with private streets and lists a spa, pool and clubhouse. The ground climbs from 293 feet to 457 feet and every parcel drains to Salt Creek. The 2025 fire hazard layer rates the entire 33.6 acres Very High, though the city records no fuel modification requirement on any parcel inside it. The flood layer places the whole boundary in zone X.

Siena is a hole cut in the middle of Marina Hills. The city draws it as its own gated polygon inside the larger association's boundary, and Siena names Marina Hills Planned Community Association as its master, alongside Chandon and Encore. Two streets serve the whole community, Siena and Pienza Street, both Tuscan, and the city's record puts the houses between 1987 and 1994 with a median of 1991.

Modern Laguna Niguel began in 1959, when Cabot, Cabot & Forbes and Paine Webber formed the Laguna Niguel Corporation and hired the Viennese architect Victor Gruen to draw a 7,100 acre town plan. AVCO Community Developers bought the corporation in 1971 and the city incorporated on 1 December 1989. Siena covers 34 acres climbing from 293 feet to 457 feet, all of it draining to Salt Creek, with a pool, a spa and a clubhouse on the association's record.