Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Interchange 4 | Crossing | 241 | Johnson | 41 45 10 N | 091 38 31 W |
| Interchange 4 | Crossing | 301 | Pottawattamie | 41 13 44 N | 095 50 21 W |
| Interchange 4 | Crossing | 229 | Scott | 41 32 17 N | 090 40 36 W |
| Interchange 40 | Crossing | 379 | Pottawattamie | 41 29 52 N | 095 20 12 W |
| Interchange 42 | Crossing | 298 | Mills | 41 08 58 N | 095 49 19 W |
| Interchange 43 | Crossing | 336 | Warren | 41 10 36 N | 093 47 01 W |
| Interchange 46 | Crossing | 392 | Pottawattamie | 41 29 50 N | 095 13 19 W |
| Interchange 47 | Crossing | 299 | Pottawattamie | 41 13 13 N | 095 49 37 W |
| Interchange 47 | Crossing | 317 | Warren | 41 13 40 N | 093 46 51 W |
| Interchange 48 | Crossing | 301 | Pottawattamie | 41 13 44 N | 095 50 21 W |
| Interchange 5 | Crossing | 308 | Pottawattamie | 41 14 32 N | 095 49 24 W |
| Interchange 51 | Crossing | 381 | Cass | 41 29 50 N | 095 07 24 W |
| Interchange 51 | Crossing | 303 | Pottawattamie | 41 14 02 N | 095 53 51 W |
| Interchange 52 | Crossing | 300 | Pottawattamie | 41 14 33 N | 095 54 16 W |
| Interchange 52 | Crossing | 313 | Warren | 41 17 36 N | 093 46 48 W |
| Interchange 53A | Crossing | 299 | Pottawattamie | 41 15 15 N | 095 54 26 W |
| Interchange 53B | Crossing | 304 | Pottawattamie | 41 15 45 N | 095 54 31 W |
| Interchange 54 | Crossing | 402 | Cass | 41 29 50 N | 095 03 36 W |
| Interchange 54A | Crossing | 297 | Pottawattamie | 41 16 15 N | 095 54 31 W |
| Interchange 54B | Crossing | 299 | Pottawattamie | 41 16 15 N | 095 54 06 W |
| Interchange 55 | Crossing | 309 | Pottawattamie | 41 16 30 N | 095 52 51 W |
| Interchange 56 | Crossing | 260 | Warren | 41 21 46 N | 093 46 49 W |
| Interchange 57 | Crossing | 391 | Cass | 41 29 50 N | 095 00 14 W |
| Interchange 6 | Crossing | 229 | Scott | 41 30 32 N | 090 40 21 W |
| Interchange 60 | Crossing | 366 | Cass | 41 29 50 N | 094 56 41 W |
| Interchange 62 | Crossing | 302 | Pottawattamie | 41 21 18 N | 095 54 01 W |
| Interchange 64 | Crossing | 384 | Cass | 41 29 50 N | 094 52 07 W |
| Interchange 65 | Crossing | 296 | Warren | 41 29 00 N | 093 46 48 W |
| Interchange 66 | Crossing | 306 | Pottawattamie | 41 25 10 N | 095 54 01 W |
| Interchange 68 | Crossing | 254 | Polk | 41 31 35 N | 093 46 23 W |
| Interchange 69 | Crossing | 263 | Polk | 41 32 30 N | 093 46 31 W |
| Interchange 70 | Crossing | 401 | Cass | 41 29 50 N | 094 45 31 W |
| Interchange 71 | Crossing | 304 | Pottawattamie | 41 29 38 N | 095 54 04 W |
| Interchange 72 | Crossing | 305 | Pottawattamie | 41 29 58 N | 095 54 05 W |
| Interchange 75 | Crossing | 421 | Adair | 41 29 35 N | 094 39 41 W |
| Interchange 75 | Crossing | 308 | Harrison | 41 33 00 N | 095 55 02 W |
| Interchange 76 | Crossing | 438 | Adair | 41 29 35 N | 094 38 36 W |
| Interchange 8 | Crossing | 356 | Pottawattamie | 41 16 49 N | 095 47 03 W |
| Interchange 8 | Crossing | 189 | Scott | 41 29 30 N | 090 39 01 W |
| Interchange 82 | Crossing | 309 | Harrison | 41 37 12 N | 095 59 16 W |
| Interchange 83 | Crossing | 395 | Adair | 41 29 45 N | 094 31 11 W |
| Interchange 86 | Crossing | 402 | Adair | 41 29 45 N | 094 27 09 W |
| Interchange 88 | Crossing | 384 | Adair | 41 29 45 N | 094 24 41 W |
| Interchange 89 | Crossing | 312 | Harrison | 41 42 40 N | 096 02 41 W |
| Interchange 90 | Crossing | 282 | Polk | 41 42 10 N | 093 34 35 W |
| Interchange 92 | Crossing | 280 | Polk | 41 43 55 N | 093 34 36 W |
| Interchange 93 | Crossing | 370 | Adair | 41 29 35 N | 094 19 06 W |
| Interchange 95 | Crossing | 319 | Harrison | 41 48 07 N | 096 03 19 W |
| Interchange 96 | Crossing | 301 | Polk | 41 47 29 N | 093 34 13 W |
| Interchange 97 | Crossing | 347 | Adair | 41 29 36 N | 094 14 29 W |
| Interchange RV Campgrounds | Locale | 318 | Monona | 42 01 30 N | 096 07 33 W |
| Interdenominational New Life Fellowship | Church | 306 | Pottawattamie | 41 16 23 N | 095 52 44 W |
| Internal Medicine Associates Center | Hospital | 325 | Pottawattamie | 41 16 05 N | 095 50 24 W |
| Internal Medicine Center | Hospital | 351 | Boone | 42 03 22 N | 093 52 42 W |
| Internal Medicine Center Incorporated | Hospital | 214 | Des Moines | 40 48 38 N | 091 10 16 W |
| Internal Medicine Consultants | Hospital | 396 | Union | 41 04 12 N | 094 23 03 W |
| Internal Medicine of Ottumwa Center | Hospital | 255 | Wapello | 41 01 45 N | 092 23 23 W |
| International Cemetery | Cemetery | 285 | Benton | 41 53 53 N | 092 10 49 W |
| International Center | Building | 210 | Johnson | 41 39 53 N | 091 32 33 W |
| International Center | Building | 267 | Linn | 41 55 36 N | 091 25 27 W |
| International Center | Building | 293 | Polk | 41 36 03 N | 093 39 18 W |
| International House | Building | 228 | Linn | 41 59 18 N | 091 39 28 W |
| International Order of Odd Fellows Cemetery | Cemetery | 325 | Dubuque | 42 36 15 N | 090 47 28 W |
| International Order of Odd Fellows Cemetery | Cemetery | 266 | Iowa | 41 43 40 N | 092 17 21 W |
| International Order of Odd Fellows Cemetery | Cemetery | 231 | Iowa | 41 47 19 N | 092 03 21 W |
| International Order of Odd Fellows Cemetery | Cemetery | 271 | Poweshiek | 41 44 05 N | 092 25 54 W |
| International Wrestling Institute and Museum | Building | 264 | Jasper | 41 41 05 N | 093 04 54 W |
| Interstate 182 | Crossing | 301 | Poweshiek | 41 41 46 N | 092 43 37 W |
| Interstate Grain Incorporated Elevator | Locale | 363 | Cerro Gordo | 43 08 15 N | 093 15 34 W |
| Interstate Lake Park | Park | 376 | Franklin | 42 43 47 N | 093 25 01 W |
| Interstate Park | Park | 336 | Mitchell | 43 19 10 N | 092 52 52 W |
| Interstate Power Fishing Access Area | Locale | 190 | Allamakee | 43 20 15 N | 091 10 20 W |
| Interstate RV Park and Campground | Locale | 221 | Scott | 41 36 18 N | 090 37 51 W |
| Interstate Thirty-Five High School | School | 332 | Madison | 41 12 40 N | 093 50 34 W |
| Interstate Thirty-Five School | School | 329 | Warren | 41 10 48 N | 093 43 32 W |
| Inwood | Populated Place | 447 | Lyon | 43 18 26 N | 096 25 55 W |
| Inwood (historical) | Locale | 448 | Lyon | 43 18 20 N | 096 25 59 W |
| Inwood Christian Reformed Church | Church | 446 | Lyon | 43 18 40 N | 096 25 47 W |
| Inwood Christian School | School | 448 | Lyon | 43 18 19 N | 096 25 43 W |
| Inwood Park Beach | Beach | 427 | Dickinson | 43 27 30 N | 095 05 18 W |
| Inwood Post Office | Post Office | 447 | Lyon | 43 18 25 N | 096 25 54 W |
| Inwood Public Library | Building | 447 | Lyon | 43 18 28 N | 096 25 54 W |
| Inwood Woodcarving Exhibit | Building | 290 | Dubuque | 42 29 04 N | 091 07 22 W |
| Ioka (historical) | Populated Place | 243 | Keokuk | 41 10 57 N | 092 07 45 W |
| Ioka Post Office (historical) | Post Office | 243 | Keokuk | 41 10 57 N | 092 07 45 W |
| Iola (historical) | Populated Place | 363 | Pottawattamie | 41 19 58 N | 095 22 48 W |
| Iola Post Office (historical) | Post Office | 245 | Marion | 41 20 25 N | 092 58 24 W |
| Ion | Populated Place | 208 | Allamakee | 43 06 46 N | 091 15 43 W |
| Ion Methodist Cemetery | Cemetery | 240 | Allamakee | 43 06 57 N | 091 15 38 W |
| Ion Post Office (historical) | Post Office | 208 | Allamakee | 43 06 46 N | 091 15 43 W |
| Ione Post Office (historical) | Post Office | 245 | Iowa | 41 35 26 N | 091 54 46 W |
| Ionia | Locale | 349 | Chickasaw | 43 02 04 N | 092 27 21 W |
| Ionia | Populated Place | 350 | Chickasaw | 43 02 03 N | 092 27 22 W |
| Ionia Community Library | Building | 349 | Chickasaw | 43 02 04 N | 092 27 21 W |
| Ionia Post Office | Post Office | 349 | Chickasaw | 43 02 04 N | 092 27 21 W |
| Iowa Advanced Technology Laboratories | Building | 199 | Johnson | 41 39 51 N | 091 32 17 W |
| Iowa Arboretum | Park | 292 | Boone | 41 56 40 N | 093 51 26 W |
| Iowa Army Ammunition Plant Dam | Dam | 183 | Des Moines | 40 46 57 N | 091 15 11 W |
| Iowa Aviation Preservation Center | Building | 416 | Adair | 41 19 30 N | 094 26 36 W |
| Iowa Band Museum | Building | 263 | Black Hawk | 42 32 17 N | 092 26 50 W |
| Iowa Braille and Sightsaving School | School | 247 | Benton | 42 09 43 N | 092 02 03 W |
| Iowa Center | Populated Place | 289 | Story | 41 55 43 N | 093 24 19 W |
| Iowa Center Post Office (historical) | Post Office | 289 | Story | 41 55 43 N | 093 24 19 W |
| Iowa Central Community College | School | 445 | Buena Vista | 42 35 53 N | 095 12 40 W |
| Iowa Central Community College | School | 333 | Hamilton | 42 27 36 N | 093 50 12 W |
| Iowa Central Community College | School | 340 | Webster | 42 29 20 N | 094 12 13 W |
| Iowa Central Community College | School | 341 | Wright | 42 40 02 N | 093 54 18 W |
| Iowa Church of God in Christ | Church | 233 | Linn | 41 59 02 N | 091 38 44 W |
| Iowa City | Civil | 210 | Johnson | 41 39 30 N | 091 32 07 W |
| Iowa City | Populated Place | 204 | Johnson | 41 39 40 N | 091 31 49 W |