Iowa - Significance region: Local
| Chicago, Burlington and Quincy Railroad-Creston Station |
| Chicago, Burlington and Quincy Station |
| Chicago, Great Western Railroad-Waterloo Freight Depot |
| Chicago, Milwaukee and Pacific Railroad-Albert City Station |
| Chicago, Milwaukee, and St. Paul Railroad-Grafton Station |
| Chicago, Milwaukee, St. Paul and Pacific Freight House |
| Chicago, Milwaukee, St. Paul and Pacific Railroad Company Depot |
| Chicago, Milwaukee & St. Paul Depot-Jefferson |
| Chicago, Milwaukee, St. Paul & Pacific Depot-Delmar |
| Chicago, Rock Island and Pacific Passenger Depot-Pella |
| Chicago, Rock Island and Pacific Railroad Passenger Depot |
| Chicago, Rock Island and Pacific Railroad Passenger Station |
| Chicago, Rock Island and Pacific Railroad Stone Arch Viaduct |
| Chicago,Rock Island and Pacific Railroad: Stuart Passenger Station |
| Chicago, Rock Island and Pacific Railroad-Wilton Depot |
| Chicago, Rock Island & Pacific Railroad Depot |
| Chickasaw County Courthouse |
| Christiansen, Jens Otto, House |
| Church of St. John the Baptist |
| Church of the Saviour Episcopal Church and David Henderson Statue |
| Church, Seymour, House |
| City Hall |
| City Hotel |
| City Market |
| Civic Center Historic District |
| Civilian Conservation Corps-Prisoner of War Recreation Hall |
| Clarinda Carnegie Library |
| Clark, Gerome, House |
| Clark House |
| Claussen, William, House |
| Clay County Courthouse |
| Clayton County Courthouse |
| Clayton School |
| Clear Lake Lake Wall |
| Clemens Automobile Company Building |
| Clermont Public School |
| Clifton |
| Clinton County Courthouse |
| Clinton High School and Public Library |
| Close House |
| Coal Ridge Baptist Church and Cemetery |
| Cody Homestead |
| Cody Road Historic District |
| Coggon Commercial Historic District |
| Coggon Public School |
| Coldwater Church of the Brethren |
| Colfax Spring City Commercial Historic District |
| College Block Building |
| College Corner Commercial Historic Business District |
| College Green Historic District |
| College Square Historic District |
| Collegiate Neighborhood Historic District |
| Collins-Bond House |
| Collins House |
| Colonials Club House |
| Columbia Avenue Historic District |
| Columbus Junction School 1882-1920 |
| Commercial Hotel |
| Community Building |
| Conant's Cabin and Park |
| Concord Congregational Cemetery |
| Conger, Jonathan Clark, House |
| Conover, Thomas J., House |
| Consistory Building No. 2 |
| Cook, Clarissa, Home for the Friendless |
| Cook-Johnson House |
| Cooley-Whitney House |
| Cooper, George and Margaret, House |
| Cooper, George, House |
| Copeland, George, House |
| Coralville Public School |
| Coralville Union Ecclesiastical Church |
| Corbett's-Eby's Mill Bridge |
| Cork Hill District |
| Cornell College-Mount Vernon Historic District |
| Cornell, W. J. and Nettie J., House |
| Corning Commercial Historic District |
| Corning Opera House |
| Cottage at 1514 and 1516 W. Second Street |
| Cottage at Rock and Dubuque Streets |
| Cottage Grove Avenue Presbyterian Church |
| Cottage Hill Methodist-Episcopal Cemetery |
| Cotton Theater |
| Council Bluffs Federal Building and Post Office |
| Council Bluffs Free Public Library |
| Council Bluffs Telephone Exchange |
| Court Hill Historic District |
| Courthouse Square Historic District |
| Cowles, George H and Alice Spaulding, House |
| Crane Building |
| Cranford Apartment Building |
| Crapo Park and Arboretum Historic District |
| Craven, J. D., Women's Relief Corps Hall |
| Crawford County Courthouse |
| Crawford House |
| Crescent Warehouse Historic District |
| Cresco Opera House |
| Cretsinger, John, House |
| Crozier, J.T. and Mollie, House |
| C.S.P.S. Hall |
Data from United States Park Service and Wikidata
