Orange County (OC) is a county in Southern California, United States. Its county seat is Santa Ana. The state of California estimates its population as of 2008 to be 3,121,251, dropping its rank to third, behind San Diego County.

Orange County is defined mostly by its suburban make-up with various commerce and industrial centers and by its spectacular coastline.  The architectural fabric of Orange County varies by the older North county and newer South County demographic.  North County has older, more urban neighborhoods with a more diverse architectural fabric.  South County has a greater planned community feel with a more homogenous Mediterranean design.

Oldham Architects provides service to the following cities in Orange County:

Aliso Viejo
Anaheim
Atwood
Brea
Buena Park
Capistrano Beach
Corona del Mar
Costa Mesa
Coto de Caza
Cypress
Dana Point
El Toro
Foothill Ranch
Fountain Valley
Fullerton
Garden Grove
Huntington Beach
Irvine
La Habra
La Palma
Laguna Beach
Laguna Hills
Laguna Niguel
Laguna Woods
Lake Forest
Los Alamitos
Midway City
Mission Viejo
Monarch Beach
Newport Beach
Orange
Placentia
Rancho Santa Margarita
San Clemente
San Juan Capistrano
Santa Ana
Santa Ana Heights
Seal Beach
Silverado
South Laguna
Stanton
Sunset Beach
Surfside
Trabuco Canyon
Tustin
Villa Park
Westminster
Yorba Linda
Turtle Ridge
Serrano Heights
Newport Coast