Illinois - Criteria: C (architecture/engineering)
| Central Manufacturing District-Pershing Road Development Historic District |
| Central National Park Building |
| Central Park Theater |
| Cermak Road Bridge Historic District |
| Chain of Rocks Bridge |
| Champaign Downtown Commercial District |
| Chana School |
| Chanute Field Historic District |
| Chapin and Gore Building |
| Charnley, James, House |
| Charter Oak Schoolhouse |
| Chautauqua Auditorium |
| Chemical Laboratory |
| Chicago and Northwestern Depot |
| Chicago and North Western Railroad Depot |
| Chicago and North Western Railway Power House |
| Chicago Avenue Water Tower and Pumping Station |
| Chicago Beach Hotel |
| Chicago Bee Building |
| Chicago, Burlington, and Quincy Railroad Depot |
| Chicago, Burlington, & Quincy Roundhouse and Locomotive Shop |
| Chicago Club |
| Chicago Federal Center |
| Chicago Public Library, Central Building |
| Chicago Sanitary and Ship Canal Historic District |
| Chicago Savings Bank Building |
| Chicago Telephone Company Kedzie Exchange |
| Chicago Varnish Company Building |
| Chick House |
| Children's Village-Illinois Soldiers' and Sailors' Children's School |
| Childs, Robert A. and Mary, House |
| Chipman, Edith, House |
| Chippiannock Cemetery |
| Christ Church of Lower Kickapoo |
| Christ Episcopal Church |
| Christ Episcopal Church |
| Christian Hill Historic District |
| Churchill, Richard, House |
| Church of Christ |
| Church of the Epiphany |
| Church of the Holy Family |
| Church of the St. Sava Serbian Orthodox Monastery |
| City Building |
| Clarke, Henry B., House |
| Clay County Courthouse |
| Clay County Jail |
| Clayson, George, House |
| Clayville Tavern |
| Clear Creek Meeting House |
| Cloud, Aaron G., House |
| Cloud, Chalon Guard and Emma Blades, House |
| Cloud State Bank |
| Clover Lawn |
| Cluever, Richard, House |
| Coca-Cola Bottling Company Building |
| Coffeen, William and Helen, House |
| Coles County Courthouse |
| Collins, Daniel Dove, House |
| Collinsville Masonic Temple Lodge #712 A.F. & A.M. |
| Colonnade Court |
| Columbus Park |
| Compton, Dr. Charles, House |
| Condit, Cortland, House |
| Conger, J. Newton, House |
| Connor House |
| Continental and Commercial National Bank |
| Conway Building |
| Cook County Criminal Court Building |
| Cook County Hospital Administration Building |
| Cook, John W., Hall |
| Coonley, Avery, House |
| Coonley, Avery, School |
| Copley, Col. Ira C., Mansion |
| Cornell Square |
| Coronado |
| Count's House |
| Covell, Lucein Boneparte, House |
| Covent Hotel |
| Cox, George H., House |
| Crenshaw House |
| Creole House |
| Crow Island School |
| Cumberland Presbyterian Church |
| Cunningham, Andrew, Farm |
| Curtis, Elijah P., House |
| Dale Building |
| Dana, Susan Lawrence, House |
| Danville Branch, National Home for Disabled Volunteer Soldiers Historic District |
| Danville Public Library |
| Davis, David, III & IV, House |
| Davis Square |
| Dawson Brothers Plant |
| Dearborn Station |
| Decatur Downtown Historic District |
| Decatur Historic District |
| Deerpath Hill Estates Historic District |
| Deerpath Inn |
| Delavan Commercial Historic District |
| Delaware Building |
| Delta Upsilon Fraternity House |
Data from United States Park Service and Wikidata
