Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Iowa Slough Lake | Lake | 161 | Des Moines | 41 04 30 N | 090 58 46 W |
| Iowa Soldiers Home | Locale | 281 | Marshall | 42 03 25 N | 092 55 60 W |
| Iowa State Capitol | Building | 273 | Polk | 41 35 28 N | 093 36 14 W |
| Iowa State Experimental Farm | Locale | 322 | Boone | 41 54 34 N | 093 48 14 W |
| Iowa State Fair Campgrounds | Locale | 289 | Polk | 41 35 41 N | 093 32 30 W |
| Iowa State Fairgrounds | Locale | 259 | Polk | 41 35 45 N | 093 32 56 W |
| Iowa State Fish Aquarium and Hatchery | Locale | 190 | Clayton | 42 46 59 N | 091 05 42 W |
| Iowa State Nursery | Park | 273 | Story | 41 59 57 N | 093 36 17 W |
| Iowa State Penal Farm | Locale | 259 | Jones | 42 06 45 N | 091 14 31 W |
| Iowa State Penitentiary | Building | 171 | Lee | 40 38 04 N | 091 17 51 W |
| Iowa State Penitentiary Heliport | Airport | 165 | Lee | 40 37 55 N | 091 17 51 W |
| Iowa State Prison Cemetery | Cemetery | 180 | Lee | 40 38 12 N | 091 17 55 W |
| Iowa State Reformatory (historical) | School | 250 | Jones | 42 06 40 N | 091 17 24 W |
| Iowa State Reformatory for Women | Locale | 369 | Calhoun | 42 23 28 N | 094 36 21 W |
| Iowa State Training School for Boys | School | 320 | Hardin | 42 21 30 N | 093 06 25 W |
| Iowa State Univ Experimental Farm Number 1 | School | 314 | Boone | 41 59 13 N | 093 41 39 W |
| Iowa State Univ Experimental Farms Number 2 | School | 306 | Story | 41 59 23 N | 093 39 25 W |
| Iowa State University | School | 293 | Story | 42 01 34 N | 093 38 55 W |
| Iowa State University Agronomy Farm | Locale | 339 | Boone | 42 01 16 N | 093 46 24 W |
| Iowa State University Allee Experimental Farm | Locale | 384 | Buena Vista | 42 35 60 N | 095 00 45 W |
| Iowa State University Arboretum | Locale | 293 | Story | 42 01 08 N | 093 39 20 W |
| Iowa State University Experimental Farm | School | 292 | Polk | 41 42 41 N | 093 37 59 W |
| Iowa State University Experimental Farm | School | 305 | Story | 42 06 31 N | 093 35 18 W |
| Iowa State University Experimental Farm Number 1 | School | 300 | Story | 42 03 28 N | 093 40 56 W |
| Iowa State University Experimental Station | School | 426 | Monona | 42 03 47 N | 095 50 10 W |
| Iowa Township Cemetery | Cemetery | 439 | Crawford | 41 55 18 N | 095 06 42 W |
| Iowa Township Park | Park | 211 | Washington | 41 29 08 N | 091 34 57 W |
| Iowa Trolley Park | Park | 366 | Cerro Gordo | 43 08 13 N | 093 20 46 W |
| Iowa Union College | Locale | 246 | Mahaska | 41 18 16 N | 092 38 29 W |
| Iowa United Pentecostal Church | Church | 268 | Black Hawk | 42 29 34 N | 092 20 58 W |
| Iowa Valley Elementary School | School | 224 | Iowa | 41 48 10 N | 092 04 09 W |
| Iowa Valley Junior and Senior High School | School | 224 | Iowa | 41 47 57 N | 092 04 01 W |
| Iowa Wesleyan College | School | 222 | Henry | 40 58 21 N | 091 33 09 W |
| Iowa West Foundation Trailhead Park | Park | 301 | Pottawattamie | 41 13 10 N | 095 49 04 W |
| Iowa Western Community College | School | 305 | Page | 40 44 20 N | 095 01 36 W |
| Iowa Western Community College | School | 323 | Pottawattamie | 41 16 25 N | 095 48 01 W |
| Iowa Western Community College | School | 370 | Shelby | 41 38 37 N | 095 19 29 W |
| Iowa-Missoura Camp | Locale | 251 | Davis | 40 37 47 N | 092 19 08 W |
| Iowana School | School | 338 | Pottawattamie | 41 17 59 N | 095 50 16 W |
| Iowas Children Museum | Building | 218 | Johnson | 41 41 30 N | 091 36 21 W |
| Iowaville Cemetery | Cemetery | 205 | Van Buren | 40 53 10 N | 092 09 47 W |
| Iowaville Post Office (historical) | Post Office | 185 | Van Buren | 40 52 45 N | 092 10 38 W |
| Ips Heliport | Airport | 337 | Woodbury | 42 29 40 N | 096 24 29 W |
| Ira | Populated Place | 261 | Jasper | 41 46 40 N | 093 12 21 W |
| Ira (historical) | Locale | 254 | Jasper | 41 46 37 N | 093 12 13 W |
| Ira Post Office (historical) | Post Office | 262 | Jasper | 41 46 40 N | 093 12 21 W |
| Iranistan Post Office (historical) | Post Office | 340 | Cass | 41 18 30 N | 095 07 41 W |
| Iranistan Rock Quarry Park | Park | 350 | Cass | 41 18 30 N | 095 08 01 W |
| Irene Post Office (historical) | Post Office | 373 | Sioux | 43 10 16 N | 096 22 07 W |
| Ireton | Populated Place | 434 | Sioux | 42 58 29 N | 096 19 06 W |
| Ireton (historical) | Locale | 417 | Sioux | 42 58 41 N | 096 19 06 W |
| Ireton Christian School | School | 433 | Sioux | 42 58 26 N | 096 18 47 W |
| Ireton Community Fire Station | Building | 432 | Sioux | 42 58 28 N | 096 19 11 W |
| Ireton Family Practice Building | Hospital | 431 | Sioux | 42 58 31 N | 096 19 05 W |
| Ireton Medical Clinic | Hospital | 432 | Sioux | 42 58 31 N | 096 19 07 W |
| Ireton Post Office | Post Office | 433 | Sioux | 42 58 30 N | 096 19 07 W |
| Irish Grove Post Office (historical) | Post Office | 298 | Lucas | 41 02 00 N | 093 09 11 W |
| Irish Hollow Creek | Stream | | Allamakee | 43 27 30 N | 091 19 40 W |
| Irish Lake | Lake | 323 | Monona | 42 07 58 N | 096 08 46 W |
| Iron Hills Post Office (historical) | Post Office | 288 | Jackson | 42 08 30 N | 090 46 11 W |
| Ironhills | Populated Place | 288 | Jackson | 42 08 30 N | 090 46 11 W |
| Iroquois Park | Park | 246 | Linn | 41 57 51 N | 091 37 53 W |
| Irv Warren Memorial Golf Course | Locale | 263 | Black Hawk | 42 28 50 N | 092 22 21 W |
| Irving | Populated Place | 260 | Benton | 41 56 54 N | 092 17 43 W |
| Irving (historical) | Locale | 245 | Tama | 41 56 48 N | 092 18 11 W |
| Irving Cemetery | Cemetery | 279 | Benton | 41 57 02 N | 092 16 48 W |
| Irving Junior High School | School | 281 | Polk | 41 36 11 N | 093 38 18 W |
| Irving Post Office (historical) | Post Office | 254 | Tama | 41 56 48 N | 092 18 01 W |
| Irving School | School | 266 | Black Hawk | 42 28 51 N | 092 20 54 W |
| Irving School | School | 253 | Dubuque | 42 29 57 N | 090 42 09 W |
| Irving School | School | 251 | Linn | 42 02 11 N | 091 36 10 W |
| Irving School | School | 386 | Union | 41 04 03 N | 094 21 42 W |
| Irving School | School | 197 | Wapello | 41 00 18 N | 092 25 33 W |
| Irving School | School | 288 | Warren | 41 21 50 N | 093 34 00 W |
| Irving School | School | 362 | Woodbury | 42 30 05 N | 096 23 56 W |
| Irving School (historical) | School | 181 | Clinton | 41 49 46 N | 090 11 47 W |
| Irving Webster Elementary School | School | 235 | Johnson | 41 38 45 N | 091 35 41 W |
| Irvington | Locale | 351 | Kossuth | 43 00 30 N | 094 11 41 W |
| Irvington | Populated Place | 351 | Kossuth | 43 00 27 N | 094 11 44 W |
| Irvington Post Office (historical) | Post Office | 351 | Kossuth | 43 00 27 N | 094 11 44 W |
| Irwin | Populated Place | 393 | Shelby | 41 47 30 N | 095 12 21 W |
| Irwin (historical) | Locale | 387 | Shelby | 41 47 20 N | 095 12 23 W |
| Irwin Creek | Stream | | Wayne | 40 30 48 N | 093 29 13 W |
| Irwin Post Office | Post Office | 391 | Shelby | 41 47 26 N | 095 12 21 W |
| Irwin Post Office (historical) | Post Office | 410 | Audubon | 41 45 40 N | 094 52 09 W |
| Irwin Town Hall | Building | 391 | Shelby | 41 47 25 N | 095 12 21 W |
| Isaac Mason Historical Marker | Park | 270 | Davis | 40 47 41 N | 092 29 09 W |
| Isaac Walton League Park | Park | 225 | Scott | 41 36 15 N | 090 34 40 W |
| Isabell (historical) | Locale | 278 | Jones | 42 04 55 N | 091 08 51 W |
| Isabell Post Office (historical) | Post Office | 269 | Jones | 42 04 40 N | 091 09 06 W |
| Island 176 | Island | 187 | Clayton | 42 57 27 N | 091 09 28 W |
| Island 178 | Island | 187 | Clayton | 42 56 03 N | 091 09 23 W |
| Island 186 | Island | 187 | Clayton | 42 51 28 N | 091 05 05 W |
| Island 188 | Island | 187 | Clayton | 42 49 22 N | 091 05 16 W |
| Island 189 | Island | 186 | Clayton | 42 44 41 N | 091 03 53 W |
| Island Cemetery | Cemetery | 168 | Muscatine | 41 21 32 N | 091 06 43 W |
| Island Church | Church | 167 | Muscatine | 41 21 48 N | 091 05 49 W |
| Island Grove Post Office (historical) | Post Office | 304 | Butler | 42 39 60 N | 092 55 01 W |
| Island Grove Post Office (historical) | Post Office | 393 | Emmet | 43 19 18 N | 094 43 01 W |
| Island Park | Locale | 295 | Pottawattamie | 41 10 29 N | 095 48 50 W |
| Island Park | Park | 262 | Black Hawk | 42 32 42 N | 092 27 09 W |
| Island Park | Park | 408 | Lyon | 43 26 20 N | 096 10 05 W |
| Island Park | Park | 301 | Webster | 42 30 13 N | 094 12 04 W |
| Island Park Campground | Locale | 412 | Lyon | 43 26 17 N | 096 09 59 W |
| Island View Park | Park | 276 | Appanoose | 40 50 50 N | 092 55 01 W |
| Islandpark Post Office (historical) | Post Office | 295 | Pottawattamie | 41 10 29 N | 095 48 50 W |
| Isley Field | Airport | 302 | Black Hawk | 42 31 15 N | 092 31 10 W |
| Isolation Hospital (historical) | Hospital | 205 | Scott | 41 32 41 N | 090 35 41 W |
| Israel Day Lake | Lake | 178 | Jackson | 42 05 14 N | 090 10 24 W |
| Isted Post Office (historical) | Post Office | 291 | Winneshiek | 43 22 29 N | 091 37 51 W |