Community History
- Anaheim Colony Historic District
- Huntington Beach History
- Mission Viejo Heritage Committee
- Olive Through the Ages – History of Olive, CA
- OC Historyland
Historical Societies
- Anaheim Historical Society
- Buena Park Historical Society
- Costa Mesa Historical Society
- Dana Point Historical Society
- Garden Grove Historical Society
- Irvine Historical Society
- Laguna Beach Historical Society
- Laguna Niguel Historical Society
- Laguna Woods History Center
- Modjeska Foundation
- Newport Beach Historical Society
- Orange Community Historical Society
- O.C. Jewish Historical Society
- Placentia Founders Society
- Rancho Santa Margarita Historical Society
- San Clemente Historical Society
- San Juan Capistrano Historical Society
- Santa Ana Black Historical Society
- Southern California Railway Plaza Association
- Tustin Area Historical Society
Museums
- Balboa Island Museum and Historical Society
- Blas-Aguilar Adobe
- Bowers Museum
- Brea Museum & Heritage Center
- Heritage Museum of Orange County
- Historical Parks (OC Parks)
- Dr. Willella Howe-Waffle House
- International Surfing Museum
- La Habra Historical Museum
- Mission San Juan Capistrano
- Nixon Presidential Library & Museum
- O.C. Agricultural & Nikkei Heritage Museum
- Pilgrim (Tallship)
- Surfing Heritage Foundation
- Susanna Bixby Bryant Ranch House & Museum
- Tustin Area Museum
Preservation
- Preserve Orange County
- Fullerton Heritage
- Fullerton Historic Theatre Foundation
- Mills Act Tax Abatement Program
- Old Towne Preservation Association (Orange)
- Santa Ana Historical Preservation Society
- Tustin Preservation Conservancy
Research
- Anaheim Heritage Center
- California State Archives
- Calisphere (Photos)
- Center For Oral & Public History, CSUF
- Documentation & Conservation of the Modern Movement, SoCal
- First American Corp. (Photos)
- Fullerton Local History Room
- National Archives, Pacific Region
- Online Archive of California
- Orange County Archives
- Orange Public Library and History Center
- Placentia Library History Room
- Orange County Genealogical Society
- Santa Ana Public Library History Room
- Sherman Library
- UCI Special Collections
- Yorba Linda History Room