California - Area of significance: Architecture
| C.A. THAYER |
| Catholic-Protestant Chapels, Veterans Administration Center |
| Cecil Ranch |
| Centinela Adobe |
| Central Embarcadero Piers Historic District |
| Chamber of Commerce Building |
| Chambord Apartments |
| Chapel of the Transfiguration |
| Chaplain's House |
| Chapman, A. H., House |
| Chapman Building |
| Chapman, John G., House |
| Charmont Apartments |
| Chateau Chevalier |
| Chateau Colline |
| Chateau Pacheteau |
| Childs, William, House |
| China Camp |
| Choy, Sam, Brick Store |
| Christian Church of Gilroy |
| Christiancy, George A. C., House |
| Christian Science Society |
| Churchill Manor |
| Church of St. Joseph |
| Church of the Epiphany |
| Church of the Good Shepherd-Episcopal |
| Church of the Nativity |
| Citizens Publishing Company Building |
| Citrus Square Historic District |
| City Hall |
| City Hall-City of Burbank |
| City Hotel |
| City of Paris Building |
| City of San Diego Police Headquarters, Jails and Courts |
| City Transfer and Storage Company Warehouse |
| Civic Art Gallery |
| Civic Center Financial District |
| Clark, Dr. George C., House |
| Clarke Estate |
| Clark, Mary Andrews, Memorial Home |
| Clark, William S., House |
| Clay Building |
| Clayton Vineyards-DeMartini Winery |
| Clotfelter, Reginald M. and Constance, Row House |
| Cloverdale Railroad Station |
| Cloyne Court Hotel |
| Club Casa Del Mar |
| Cnopius House |
| Coachella Valley Savings No. 1 |
| Coachella Valley Savings No. 2 |
| Coalinga Polk Street School |
| Coffin-Redington Building |
| Cohen, Alfred H., House |
| Cohn House |
| Cole's Five Cypress Farm |
| Colfax Freight Depot |
| Colfax Passenger Depot |
| College Women's Club |
| Colombo Building |
| Colonial Court |
| Colonial House |
| Colony House |
| Colorado Street Bridge |
| Columbia Historic District |
| Colusa Carnegie Library |
| Colusa Grammar School |
| Colusa High School and Grounds |
| Combellack-Blair House |
| Commercial and Savings Bank |
| Commercial Club |
| Commercial Exchange Building |
| Commercial Row-Brickelltown Historic District |
| Community Church of Gonzales |
| Community Clubhouse |
| Comstock House |
| Con Creek School |
| Condominium 1 |
| Cone and Kimball Building |
| Confidence Hall |
| Congdon, Joel R., House |
| Congregation B'nai B'rith |
| Congregation Talmud Torah of Los Angeles |
| Connell, Arthur and Kathleen, House |
| Contra Costa County Courthouse Block |
| Contra Costa County Hall of Records |
| Cook, Maj. George Beecher, House |
| Coolot Company Building |
| Cooper Arms |
| Cooper Cabin |
| Cope Row Houses |
| Copperopolis Armory |
| Copperopolis Congregational Church |
| Corder Building |
| Corona High School |
| Cosby, James Fielding, House |
| Coso Hot Springs |
| Cottage Court |
| Cottonwood Historic District |
| Cottrell, John A., House |
| Coulter House |
Data from United States Park Service and Wikidata
