Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Township of Woodland | Civil | 284 | Decatur | 40 41 10 N | 093 37 02 W |
| Township of Woolstock | Civil | 344 | Wright | 42 36 06 N | 093 47 37 W |
| Township of Worth | Civil | 327 | Boone | 41 59 50 N | 093 51 51 W |
| Township of Wright | Civil | 360 | Pottawattamie | 41 17 26 N | 095 12 39 W |
| Township of Wright | Civil | 305 | Wayne | 40 51 25 N | 093 08 58 W |
| Township of Wyacondah | Civil | 264 | Davis | 40 39 11 N | 092 27 47 W |
| Township of Wyoming | Civil | 272 | Jones | 42 04 24 N | 090 57 46 W |
| Township of Yell | Civil | 313 | Boone | 42 04 24 N | 094 00 04 W |
| Township of Yell | Civil | 341 | Webster | 42 18 55 N | 093 59 47 W |
| Township of Yellow Springs | Civil | 236 | Des Moines | 41 01 39 N | 091 10 39 W |
| Township of York | Civil | 244 | Iowa | 41 38 45 N | 091 53 20 W |
| Township of York | Civil | 399 | Pottawattamie | 41 22 36 N | 095 33 25 W |
| Township of York | Civil | 260 | Tama | 41 59 39 N | 092 21 29 W |
| Tracey Church | Church | 214 | Marion | 41 16 27 N | 092 52 48 W |
| Tracey Creek | Stream | | Marion | 41 16 06 N | 093 09 11 W |
| Tracy | Locale | 224 | Marion | 41 16 41 N | 092 52 40 W |
| Tracy | Populated Place | 239 | Marion | 41 16 35 N | 092 52 32 W |
| Tracy Christian Reformed Church | Church | 239 | Marion | 41 16 35 N | 092 52 32 W |
| Tracy Farm Cemetery | Cemetery | 226 | Jackson | 42 10 50 N | 090 48 24 W |
| Tracy Post Office | Post Office | 239 | Marion | 41 16 35 N | 092 52 32 W |
| Tracy United Methodist Church | Church | 239 | Marion | 41 16 35 N | 092 52 32 W |
| Trade/Technical Building | Building | 433 | Sioux | 43 11 05 N | 095 52 51 W |
| Traders Point (historical) | Locale | 295 | Mills | 41 09 30 N | 095 50 46 W |
| Trades and Industry Building | Building | 345 | Hardin | 42 31 42 N | 093 16 03 W |
| Traer | Populated Place | 279 | Tama | 42 11 37 N | 092 27 56 W |
| Traer (historical) | Locale | 282 | Tama | 42 11 32 N | 092 27 56 W |
| Traer City Hall | Building | 280 | Tama | 42 11 35 N | 092 27 54 W |
| Traer Covenant Clinic | Hospital | 280 | Tama | 42 11 35 N | 092 27 57 W |
| Traer Fire Station House | Building | 280 | Tama | 42 11 35 N | 092 27 54 W |
| Traer Municipal Airport | Airport | 270 | Tama | 42 11 57 N | 092 27 29 W |
| Traer Post Office | Post Office | 277 | Tama | 42 11 42 N | 092 27 54 W |
| Traer Public Library | Building | 280 | Tama | 42 11 35 N | 092 27 57 W |
| Traer United Methodist Church | Church | 288 | Tama | 42 11 28 N | 092 27 57 W |
| Trail Rest Area | Locale | 251 | Black Hawk | 42 27 35 N | 092 16 46 W |
| Trainland USA | Building | 240 | Jasper | 41 40 50 N | 093 14 46 W |
| Tranquillity | Locale | 314 | Appanoose | 40 46 06 N | 093 02 24 W |
| Transit Plaza Shopping Center | Locale | 349 | Woodbury | 42 28 34 N | 096 22 33 W |
| Transportation Services Building | Building | 281 | Story | 42 01 55 N | 093 38 24 W |
| Trappers Bay | Bay | 445 | Dickinson | 43 27 16 N | 095 19 54 W |
| Trappers Bay State Park | Park | 445 | Dickinson | 43 27 13 N | 095 20 05 W |
| Traxler (historical) | Populated Place | 200 | Henry | 41 01 40 N | 091 34 51 W |
| Traxler Cemetery | Cemetery | 215 | Henry | 41 02 30 N | 091 35 31 W |
| Traxler Post Office (historical) | Post Office | 200 | Henry | 41 01 40 N | 091 34 51 W |
| Trebilcock Family Plot | Cemetery | 379 | Worth | 43 17 30 N | 093 17 31 W |
| Tree Lake | Reservoir | 368 | Mills | 41 07 48 N | 095 46 52 W |
| Tree Lake Park | Park | 368 | Mills | 41 07 48 N | 095 46 52 W |
| Tremaine Bridge | Bridge | 293 | Hamilton | 42 23 12 N | 093 48 32 W |
| Trent (historical) | Locale | 285 | Polk | 41 41 17 N | 093 35 26 W |
| Trent Post Office (historical) | Post Office | 284 | Polk | 41 41 23 N | 093 35 26 W |
| Trenton | Populated Place | 223 | Henry | 41 03 42 N | 091 38 15 W |
| Trenton Missionary Church | Church | 223 | Henry | 41 03 45 N | 091 38 23 W |
| Trenton Post Office (historical) | Post Office | 223 | Henry | 41 03 42 N | 091 38 15 W |
| Trenton United Methodist Church | Church | 223 | Henry | 41 03 45 N | 091 38 23 W |
| Trester Cemetery | Cemetery | 324 | Madison | 41 26 10 N | 094 01 07 W |
| Trettin-Cole Airport | Airport | 377 | Worth | 43 18 10 N | 093 01 38 W |
| Treynor | Populated Place | 369 | Pottawattamie | 41 13 57 N | 095 36 47 W |
| Treynor City Town Hall | Building | 366 | Pottawattamie | 41 13 55 N | 095 36 48 W |
| Treynor Elementary School | School | 368 | Pottawattamie | 41 13 57 N | 095 36 48 W |
| Treynor High School | School | 378 | Pottawattamie | 41 13 56 N | 095 36 31 W |
| Treynor Post Office | Post Office | 369 | Pottawattamie | 41 13 58 N | 095 36 48 W |
| Treynor Recreation Area | Park | 379 | Pottawattamie | 41 13 55 N | 095 36 21 W |
| Treynor Zion Congregational Cemetery | Cemetery | 379 | Pottawattamie | 41 13 58 N | 095 36 28 W |
| Tri State Family Practice Center | Hospital | 249 | Dubuque | 42 30 22 N | 090 43 10 W |
| Tri State Medical Group Center | Hospital | 185 | Lee | 40 24 24 N | 091 23 15 W |
| Tri-Center High School | School | 355 | Pottawattamie | 41 30 18 N | 095 35 42 W |
| Tri-City Jewish Cemetery | Cemetery | 218 | Scott | 41 30 42 N | 090 38 12 W |
| Tri-Club Golf Club | Locale | 337 | Clayton | 43 04 45 N | 091 28 51 W |
| Tri-County Community School | School | 267 | Keokuk | 41 27 10 N | 092 20 06 W |
| Tri-County Grain Elevator | Locale | 192 | Van Buren | 40 44 05 N | 091 57 39 W |
| Tri-County Grain Elevator | Locale | 193 | Wapello | 40 55 06 N | 092 13 11 W |
| Tri-State Fairgrounds | Locale | 211 | Des Moines | 40 48 57 N | 091 07 56 W |
| Tri-State Iron Post Historical Marker | Park | 431 | Lyon | 43 29 57 N | 096 27 07 W |
| Tri-State Raceway | Locale | 326 | Delaware | 42 28 15 N | 091 16 11 W |
| Tri-State Surgery Center | Hospital | 258 | Dubuque | 42 29 45 N | 090 44 07 W |
| Triangle Park | Park | 378 | Cerro Gordo | 43 08 29 N | 093 23 05 W |
| Triangular Park | Park | 184 | Lee | 40 24 04 N | 091 22 35 W |
| Triboji Beach | Populated Place | 429 | Dickinson | 43 25 37 N | 095 10 29 W |
| Tribute to Glenn Miller Historical Marker | Park | 305 | Page | 40 44 22 N | 095 01 34 W |
| Tribute to Madison County First Settler Historical Marker | Park | 315 | Madison | 41 19 25 N | 094 00 14 W |
| Trickle Slough | Gut | 428 | Dickinson | 43 29 53 N | 095 03 32 W |
| Trickle Slough Area | Park | 427 | Dickinson | 43 29 59 N | 095 03 46 W |
| Trienes Bay | Bay | 158 | Des Moines | 40 52 21 N | 091 02 54 W |
| Trimark Family Practice Associates Center | Hospital | 341 | Webster | 42 30 31 N | 094 10 41 W |
| Trimark Orthopaedics and Podiatry Center | Hospital | 340 | Webster | 42 28 19 N | 094 11 49 W |
| Trimark Physician Group Center | Hospital | 340 | Webster | 42 28 19 N | 094 11 49 W |
| Trimark Physicians Center | Hospital | 375 | Pocahontas | 42 44 29 N | 094 40 41 W |
| Trimark Physicians Clinic | Hospital | 355 | Wright | 42 43 16 N | 093 44 06 W |
| Trimark Physicians Group | Hospital | 385 | Buena Vista | 42 36 20 N | 095 00 10 W |
| Trimark Physicians Group | Hospital | 338 | Wright | 42 39 49 N | 093 54 07 W |
| Trimark Physicians Group Building | Hospital | 335 | Humboldt | 42 43 59 N | 094 13 53 W |
| Trimark Physicians Group Building | Hospital | 353 | Humboldt | 42 52 06 N | 094 17 23 W |
| Trimark Physicians Group Building | Hospital | 370 | Sac | 42 25 07 N | 094 58 46 W |
| Trimark Physicians Group Building | Hospital | 382 | Sac | 42 18 19 N | 095 03 07 W |
| Trimark Physicians Group Center | Hospital | 378 | Calhoun | 42 31 48 N | 094 31 58 W |
| Trimark Physicians Group Center | Hospital | 372 | Pocahontas | 42 34 50 N | 094 50 47 W |
| Trimble United Methodist Church | Church | 364 | Woodbury | 42 31 02 N | 096 23 28 W |
| TriMello | Locale | 429 | Clay | 43 04 08 N | 095 22 12 W |
| TriMello Cemetery | Cemetery | 433 | Clay | 43 04 06 N | 095 22 23 W |
| Trimello Post Office (historical) | Post Office | 429 | Clay | 43 04 08 N | 095 22 12 W |
| Trindle Park | Park | 305 | Dallas | 41 31 25 N | 093 56 51 W |
| Trinity American Lutheran Church | Church | 262 | Black Hawk | 42 29 30 N | 092 20 39 W |
| Trinity Baptist Church | Church | 292 | Polk | 41 32 34 N | 093 39 09 W |
| Trinity Bible Church | Church | 255 | Linn | 42 01 15 N | 091 39 07 W |
| Trinity Bible Church | Church | 252 | Linn | 42 02 45 N | 091 34 59 W |
| Trinity Cemetery | Cemetery | 363 | Calhoun | 42 28 29 N | 094 27 21 W |
| Trinity Cemetery | Cemetery | 421 | Cherokee | 42 44 05 N | 095 49 13 W |
| Trinity Cemetery | Cemetery | 354 | Franklin | 42 45 60 N | 093 15 08 W |
| Trinity Cemetery | Cemetery | 220 | Henry | 41 01 03 N | 091 23 23 W |
| Trinity Cemetery | Cemetery | 266 | Iowa | 41 43 27 N | 091 59 48 W |
| Trinity Cemetery | Cemetery | 296 | Poweshiek | 41 46 17 N | 092 35 31 W |