Ohio - Significance region: Local
| Cahill, Beck and R. C., Buildings |
| Cahill, Michael, House |
| Cahoon, Samuel C., House |
| Cahoon, Wilbur, House |
| Caldwell Downtown Historic District |
| Caldwell, Samuel, House |
| Caledonia Public Square and North Water Street Historic District |
| Calvary Presbyterian Church |
| Camden City Hall and Opera House |
| Camden Public School |
| Campbell, Hugh, House |
| Campbell School |
| Campbell, T. C., Mound |
| Camp Crowell Hilaka Historic District |
| Camp Manatoc Concord Lodge and Adirondacks Historic District |
| Camp Manatoc Dining Hall |
| Camp Manatoc Foresters Lodge and Kit Carson-Dan Boone Cabins Historic District |
| Camp Manatoc Legion Lodge |
| Canal Fulton Historic District |
| Canal Warehouse |
| Canal Winchester Methodist Church |
| Canal Winchester School |
| Cannon, Tom, Mound |
| Canton Public Library |
| Capital University Historic District |
| Cargo Warehouse |
| Carkhuff, Stacy G., House |
| Carlin, Patrick, House |
| Carlisle Fort |
| Carnegie Library |
| Carnegie Library and Henry St. Clair Memorial Hall |
| Carnegie Library of Steubenville |
| Carnegie Library Otterbein University |
| Carnegie Public Library |
| Carroll County Courthouse |
| Carroll, John, University North Quad Historic District |
| Carroll Township Hall |
| Carty, J.-R. J. Tussing House |
| Cary, Freeman Grant, Pleasant Hill Academy |
| Cary, G.W., House |
| Cary, Hiram W., House |
| Cary Village Site |
| Cascade Locks Historic District |
| Case-Barlow Farm |
| Casement House |
| Cassell, Henry, House |
| Casstown Lutheran Stone Church |
| Casterton House |
| Castle Block |
| Catawba Island Wine Company |
| Cawood, Richard L., Residence |
| Caxton Building |
| Cedar Branch Young Men’s Christian Association (YMCA) |
| Cedar Glen Apartments |
| Cedar Hill Cemetery Buildings |
| Cedarville Opera House |
| Celina Main Street Commercial Historic District |
| Center Inn |
| Center Street Historic District |
| Centerville Historic District |
| Central Avenue Historic District |
| Central Avenue Historic District |
| Central Building of the Columbus Young Men's Christian Association |
| Central College Presbyterian Church |
| Central High School |
| Central High School |
| Central Hotel, Hackedorn and Zimmerman Building |
| Central Public School |
| Central School |
| Central Tower Building |
| Central United Methodist Church |
| Central YMCA |
| Central YMCA |
| Century Block |
| Cermak Building |
| Chagrin Falls East Side Historic District |
| Chagrin Falls Township Hall |
| Chagrin Falls Triangle Park Commercial District |
| Chagrin Falls West Side District |
| Chalfant Church |
| Champion Coated Paper Company |
| Chandler, Matthew, House |
| Chaney, O. P., Grain Elevator |
| Chapman-Hutchinson House |
| Chapman, John A., House |
| Chardon Post Office Building |
| Cheese-vat Factory |
| Cherry Valley Coke Ovens |
| Chesapeake High School |
| Chesney, Dr. John, House |
| Chester Town Hall |
| Chester Township District School No. 2 |
| Chesterville Methodist Church |
| Chestnut Ridge Farm |
| Cheviot Fieldhouse |
| Childs, Alpha Charles, House |
| Childs, Robertus W., House |
| Chillicothe Water And Power Company Pumping Station |
| Christ Church At The Quarry |
| Christ Episcopal Church |
Data from United States Park Service and Wikidata
