Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Cantril Christian Church | Church | 237 | Van Buren | 40 38 39 N | 092 04 12 W |
| Cantril City Fire Department | Building | 237 | Van Buren | 40 38 39 N | 092 04 12 W |
| Cantril Elementary School | School | 238 | Van Buren | 40 38 40 N | 092 03 57 W |
| Cantril Post Office | Post Office | 237 | Van Buren | 40 38 39 N | 092 04 12 W |
| Cantril Public Library | Building | 237 | Van Buren | 40 38 39 N | 092 04 12 W |
| Canyon Creek | Stream | | Fremont | 40 46 59 N | 095 35 30 W |
| Canyon Creek Golf Club | Locale | 189 | Clinton | 41 54 10 N | 090 11 55 W |
| Capital City Baptist Church | Church | 290 | Polk | 41 40 05 N | 093 36 04 W |
| Capitol Gateway East Ice Pavilion | Building | 242 | Polk | 41 35 19 N | 093 36 46 W |
| Capitol Heights | Populated Place | 285 | Polk | 41 38 00 N | 093 31 13 W |
| Capitol Hill Christian Church | Church | 249 | Polk | 41 33 18 N | 093 34 11 W |
| Capoli Mill | Locale | 200 | Allamakee | 43 18 37 N | 091 14 41 W |
| Capoli Post Office (historical) | Post Office | 200 | Allamakee | 43 20 35 N | 091 12 28 W |
| Cappy Russell Access | Locale | 165 | Louisa | 41 06 05 N | 091 03 33 W |
| Capron | Locale | 320 | Marshall | 41 57 00 N | 093 00 31 W |
| Capron Post Office (historical) | Post Office | 319 | Marshall | 41 56 38 N | 093 03 33 W |
| Carbon | Populated Place | 346 | Adams | 41 02 60 N | 094 49 24 W |
| Carbon | Populated Place | 211 | Davis | 40 53 47 N | 092 25 19 W |
| Carbon (historical) | Locale | 211 | Davis | 40 53 47 N | 092 25 19 W |
| Carbon (historical) | Locale | 338 | Webster | 42 28 30 N | 094 07 33 W |
| Carbon Hill Post Office (historical) | Post Office | 213 | Davis | 40 53 50 N | 092 25 19 W |
| Carbon Junction Post Office (historical) | Post Office | 338 | Webster | 42 28 30 N | 094 07 33 W |
| Carbon Methodist Church | Church | 346 | Adams | 41 02 60 N | 094 49 24 W |
| Carbon Post Office | Post Office | 346 | Adams | 41 02 60 N | 094 49 24 W |
| Carbon Post Office (historical) | Post Office | 211 | Davis | 40 53 47 N | 092 25 19 W |
| Carbon Post Office (historical) | Post Office | 338 | Webster | 42 28 30 N | 094 07 33 W |
| Carbondale | Populated Place | 273 | Polk | 41 34 56 N | 093 30 12 W |
| Carbondale Post Office (historical) | Post Office | 230 | Mahaska | 41 19 16 N | 092 35 51 W |
| Carbondale Post Office (historical) | Post Office | 273 | Polk | 41 34 56 N | 093 30 12 W |
| Cardiff Post Office (historical) | Post Office | 357 | Mitchell | 43 19 26 N | 092 43 58 W |
| Cardinal Elementary School | School | 221 | Jackson | 42 04 34 N | 090 39 07 W |
| Cardinal Elementary School | School | 192 | Wapello | 40 54 52 N | 092 12 60 W |
| Cardinal Field | Park | 401 | Clay | 43 08 38 N | 095 07 33 W |
| Cardinal High School | School | 241 | Wapello | 40 57 40 N | 092 14 16 W |
| Cardinal Marsh State Wildlife Area | Park | 345 | Winneshiek | 43 19 53 N | 092 03 55 W |
| Cardinal Stritch High School | School | 202 | Lee | 40 25 10 N | 091 24 12 W |
| Cardiovascular Associates Center | Hospital | 355 | Woodbury | 42 32 39 N | 096 24 23 W |
| Cards Lake (historical) | Lake | 317 | Monona | 41 58 25 N | 096 05 41 W |
| Careage of Newton | Hospital | 277 | Jasper | 41 40 50 N | 093 04 33 W |
| Career Center | Building | 292 | Polk | 41 36 11 N | 093 39 10 W |
| Careers Building Complex | Building | 345 | Cerro Gordo | 43 09 30 N | 093 07 59 W |
| Cargill Grain Elevator | Locale | 277 | Fremont | 40 35 38 N | 095 39 39 W |
| Cargill Incorporated Elevator | Locale | 463 | Buena Vista | 42 40 29 N | 095 18 15 W |
| Cargill Incorporated Elevator | Locale | 316 | Dallas | 41 50 34 N | 094 13 21 W |
| Cargill Incorporated Elevator | Locale | 357 | Wright | 42 43 46 N | 093 43 60 W |
| Carl | Populated Place | 403 | Adams | 41 07 12 N | 094 39 47 W |
| Carl Cemetery | Cemetery | 399 | Adams | 41 07 17 N | 094 39 48 W |
| Carl Methodist Church | Church | 403 | Adams | 41 07 13 N | 094 39 47 W |
| Carl Post Office (historical) | Post Office | 403 | Adams | 41 07 12 N | 094 39 47 W |
| Carl Selland Park | Park | 263 | Winneshiek | 43 18 18 N | 091 47 56 W |
| Carlan Creek | Stream | | Clayton | 42 43 57 N | 091 09 40 W |
| Carleton (historical) | Locale | 262 | Polk | 41 31 17 N | 093 24 24 W |
| Carleton Post Office (historical) | Post Office | 262 | Polk | 41 31 17 N | 093 24 24 W |
| Carlin Park | Park | 357 | Woodbury | 42 32 50 N | 096 21 36 W |
| Carlisle | Locale | 240 | Warren | 41 29 55 N | 093 29 01 W |
| Carlisle | Populated Place | 260 | Warren | 41 30 03 N | 093 29 28 W |
| Carlisle Care Center | Hospital | 252 | Warren | 41 29 46 N | 093 29 36 W |
| Carlisle Cemetery | Cemetery | 263 | Marion | 41 14 01 N | 092 59 38 W |
| Carlisle Cemetery | Cemetery | 318 | Montgomery | 40 55 21 N | 094 59 02 W |
| Carlisle Cemetery | Cemetery | 249 | Warren | 41 29 27 N | 093 29 28 W |
| Carlisle Christian Church | Church | 259 | Warren | 41 30 04 N | 093 29 20 W |
| Carlisle City Fire Station | Building | 251 | Warren | 41 30 01 N | 093 29 16 W |
| Carlisle City Hall | Building | 248 | Warren | 41 30 01 N | 093 29 12 W |
| Carlisle City Park | Park | 251 | Warren | 41 30 23 N | 093 29 01 W |
| Carlisle Community Church | Church | 260 | Warren | 41 30 03 N | 093 29 28 W |
| Carlisle Community Schools | School | 253 | Warren | 41 29 53 N | 093 29 27 W |
| Carlisle Dental Office | Hospital | 244 | Warren | 41 29 35 N | 093 29 19 W |
| Carlisle Family Practice Clinic | Hospital | 244 | Warren | 41 29 55 N | 093 29 14 W |
| Carlisle Grove Cemetery | Cemetery | 305 | Benton | 42 10 23 N | 092 08 20 W |
| Carlisle Police Department | Building | 248 | Warren | 41 30 01 N | 093 29 12 W |
| Carlisle Post Office | Post Office | 243 | Warren | 41 29 54 N | 093 29 11 W |
| Carlisle Public Library | Building | 244 | Warren | 41 29 56 N | 093 29 14 W |
| Carlisle United Methodist Church | Church | 254 | Warren | 41 29 56 N | 093 29 25 W |
| Carls Creek | Stream | | Appanoose | 40 47 56 N | 093 06 55 W |
| Carlsen-Larsen Cemetery | Cemetery | 391 | Shelby | 41 34 38 N | 095 04 28 W |
| Carlson Recreation Area | Park | 284 | Webster | 42 14 10 N | 093 59 41 W |
| Carlson Stadium | Park | 268 | Winneshiek | 43 18 45 N | 091 48 26 W |
| Carlton Church | Church | 301 | Tama | 42 03 11 N | 092 44 56 W |
| Carlton Mobile Home Court | Populated Place | 255 | Linn | 42 03 00 N | 091 28 06 W |
| Carmack County Park | Park | 240 | Monroe | 41 07 10 N | 092 56 01 W |
| Carmel | Populated Place | 439 | Sioux | 43 07 40 N | 096 14 07 W |
| Carmel Church | Church | 440 | Sioux | 43 07 39 N | 096 14 04 W |
| Carmel Post Office (historical) | Post Office | 439 | Sioux | 43 07 40 N | 096 14 07 W |
| Carmel Reformed Church Cemetery | Cemetery | 441 | Sioux | 43 07 41 N | 096 13 46 W |
| Carmelite Monastery | Church | 243 | Scott | 41 40 07 N | 090 32 59 W |
| Carmichael House | Building | 340 | Decatur | 40 37 02 N | 093 55 44 W |
| Carnahan Cemetery | Cemetery | 178 | Henry | 40 52 50 N | 091 32 01 W |
| Carnarvon | Locale | 381 | Sac | 42 15 35 N | 095 00 53 W |
| Carnarvon | Populated Place | 384 | Sac | 42 15 13 N | 095 01 18 W |
| Carnarvon Post Office | Post Office | 384 | Sac | 42 15 13 N | 095 01 18 W |
| Carnegie - Stout Public Library | Building | 197 | Dubuque | 42 30 07 N | 090 40 10 W |
| Carnegie Culture Center | Building | 354 | Chickasaw | 43 03 35 N | 092 18 46 W |
| Carnegie Hall | Building | 293 | Polk | 41 36 04 N | 093 39 06 W |
| Carnegie Hall | Building | 311 | Poweshiek | 41 44 55 N | 092 43 19 W |
| Carnes | Locale | 388 | Sioux | 42 55 38 N | 096 03 25 W |
| Carnes | Populated Place | 388 | Sioux | 42 55 38 N | 096 03 25 W |
| Carnes Post Office (historical) | Post Office | 388 | Sioux | 42 55 38 N | 096 03 25 W |
| Carney | Populated Place | 325 | Floyd | 43 01 45 N | 092 48 38 W |
| Carney | Populated Place | 286 | Polk | 41 41 18 N | 093 36 02 W |
| Carney (historical) | Locale | 286 | Polk | 41 41 19 N | 093 35 39 W |
| Carney Hollow | Valley | | Clayton | 42 41 28 N | 090 59 43 W |
| Carney Park | Park | 244 | Polk | 41 33 40 N | 093 39 41 W |
| Carney Post Office (historical) | Post Office | 325 | Floyd | 43 01 45 N | 092 48 38 W |
| Carney Post Office (historical) | Post Office | 286 | Polk | 41 41 18 N | 093 36 02 W |
| Carnforth | Populated Place | 253 | Poweshiek | 41 43 20 N | 092 20 59 W |
| Carnforth (historical) | Locale | 253 | Poweshiek | 41 43 20 N | 092 20 59 W |
| Carnforth Post Office (historical) | Post Office | 253 | Poweshiek | 41 43 20 N | 092 20 59 W |
| Carp Lake | Lake | 168 | Scott | 41 28 58 N | 090 38 25 W |
| Carpenter | Locale | 363 | Mitchell | 43 24 55 N | 093 01 01 W |
| Carpenter | Populated Place | 363 | Mitchell | 43 24 54 N | 093 00 54 W |