Indiana - Criteria: C (architecture/engineering)
| Cedar Bough Place Historic District |
| Cedar Grove Bridge |
| Cedar Point Farm |
| Centennial Neighborhood District |
| Center Township Grade and High School |
| Centerville Historic District |
| Central Avenue School |
| Central Batesville Historic District |
| Central Court Historic District |
| Central High School & Boys Vocational School |
| Central Library |
| Central Library (Indianapolis-Marion County Public Library) |
| Ceylon Covered Bridge |
| Champ's Ford Bridge |
| Chapin, Horatio, House |
| Chapin Park Historic District |
| Chatham-Arch Historic District |
| Chauncey-Stadium Avenues Historic District |
| Chenoweth-Coulter Farm |
| Chesterton Commercial Historic District |
| Chesterton Residential Historic District |
| Chief Menominee Memorial Site |
| Chinworth Bridge |
| Christ Church Cathedral |
| Christian, John E. and Catherine E., House (Samara) |
| Christian Park School No. 82 |
| Christian Ridge Historic District |
| Chute, Haller T., Building |
| Circle Theater |
| Citizens Bank |
| Citizens National Bank |
| Citizens' Trust Company Building |
| City Hall |
| City Market |
| Clark, Orin, House |
| Clark, Wellington A., House |
| Clay County Courthouse |
| Clay County Hospital |
| Cline, Cyrus and Jennie, House |
| Clinton County Courthouse |
| Clore Plow Works-J.W. Whitlock and Company |
| Coambs, Norris and Harriet, Lustron House |
| Coburn, Henry P., Public School No. 66 |
| Coca-Cola Bottling Company Plant |
| Cochran-Helton-Lindley House |
| Cockrum, William M., House |
| Cole-Evans House |
| Cole, James Omar, House |
| Cole, Joseph J., Jr., House |
| Colfax Carnegie Library |
| Collett Park Neighborhood Historic District |
| Collin's Ford Bridge |
| Collins School |
| Colonial |
| Colonial Gardens Commercial Historic District |
| Colored Knights of Pythias Castle Hall |
| Colter, Ben, Polygonal Barn |
| Columbia City Historic District |
| Columbia Club |
| Columbus City Hall |
| Columbus Historic District |
| Combination Shelter |
| Combs Addition Historic District |
| Commercial Building |
| Condit House |
| Condon, Charles H. and Emma, House |
| Conklin-Montgomery House |
| Conley's Ford Bridge |
| Conn, Charles Gerard, Mansion |
| Conner's Bookstore |
| Conner Street Historic District |
| Conner, William, House |
| Convent Immaculate Conception Historic District |
| Converse Depot |
| Converse-Jackson Township Public Library |
| Conwell, Elias, House |
| Cooper-Alley House |
| Coppes, Frank and Katharine, House |
| Corbin, Roy and Iris, Lustron House |
| Cornell, William, Homestead |
| Corydon Historic District |
| Cottage Home Historic District |
| Coulter Flats |
| County Bridge #45 |
| County Line Bridge |
| Courthouse Historic District |
| Courthouse Square Historic District |
| Courthouse Square Historic District |
| Covington Courthouse Square Historic District |
| Covington Residential Historic District |
| Cox Ford Bridge |
| Cragun, Strange Nathanial, House |
| Craig, William Houston, House |
| Crawford-Gilpin House |
| Crawfordsville Commercial Historic District |
| Crawfordsville High School |
| Crawford-Whitehead-Ross House |
| Crawford-Winslow House |
| Craycraft, Daniel, House |
| Cromwell Historic District |
Data from United States Park Service and Wikidata
