Washington - Area of significance: Architecture
| Bumping Lake Cabin No. 16 |
| Bumping Lake Resort |
| Burke-Hill Apartments |
| Burlington Carnegie Library |
| Burroughs, Dr. Frank R., House |
| Burrows Island Light Station |
| Bush House |
| Butler-Jackson House |
| Butler, Norman Francis, House |
| Butterworth Building |
| Calhoun Hotel |
| California Fruit Store |
| California Ranch |
| Cama Beach Resort |
| Cambern Dutch Shop Windmill |
| Cambridge Apartments |
| Camlin Hotel |
| Campbell House |
| Camp Major Hopkins |
| Camp Muir |
| Canfield, George and Nellie. House |
| Canton, William J., House |
| Canyon Creek Shelter |
| Capital Savings and Loan Association |
| Capitol Theatre |
| Carbonneau Mansion |
| Card, Rupert, House |
| Carey, J. W., House |
| Carmichael, Elizabeth Loudon, House |
| Carmichael-Loudon House |
| Carnegie Library |
| Center School |
| Central Elementary School |
| Centralia Downtown Historic District |
| Central Service Station |
| Central Steam Heat Plant |
| Central Whidbey Island Historic District |
| Chase, Dr. Reuben, House |
| Chatter Creek Guard Station |
| Chehalis Downtown Historic District |
| Chelan Butte Lookout |
| Chelsea Family Hotel |
| Chiarelli, James and Pat, House |
| Chicago, Milwaukee, St. Paul and Pacific Railroad: South Cle Elum Yard |
| Chimacum Post Office |
| Chinook Pass Entrance Arch |
| Chittenden Locks and Lake Washington Ship Canal |
| Christ Episcopal Church |
| Christian Congregation Church of Port Ludlow |
| Christiansen, George and Blanche, House |
| Christine Falls Bridge |
| Chumasero-Smith House |
| Church of the Blessed Sacrament, Priory, and School |
| Cissna Cottages Historic District |
| City of Cheney Historic District |
| City Ramp Garage |
| Clallam County Courthouse |
| Clark County Courthouse |
| Clark Mansion |
| Clarkston Public Library |
| Clayton School |
| Clise, James W., House |
| Cloverland Garage |
| Cobb Building |
| Coder-Coleman House |
| Coffee Pot Restaurant, The |
| Colbert House |
| Coleman-Furlong House |
| Coliseum Theater |
| College Hill Historic District |
| College Park Historic District |
| Collins Building |
| Colman Automotive Building |
| Colman Building |
| Colonial Hotel |
| Colonnade Hotel |
| Columbia Building |
| Columbia City Historic District |
| Columbia County Courthouse |
| Columbia Theater |
| Colville Flour Mill |
| Commerce Building |
| Community Center and War Memorial Building |
| Continental Hotel |
| Cooney, Neil, Mansion |
| Cooper, Frank B., Elementary School |
| Copper Mountain Fire Lookout |
| Corbet-Aspray House |
| Corbin, Daniel C. and Anna, House |
| Corbin Park Historic District |
| Cordova Theater |
| Cornell Farmstead |
| Cottage Avenue Historic District |
| Courthouse and Federal Office Building |
| Covington House |
| Creaser Hotel |
| Curran, Charles and Mary Louise, House |
| Cushman No. 2 Hydroelectric Power Plant |
| Cushman Substation |
| Dadisman, David, House |
Data from United States Park Service and Wikidata
