Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Greer Cemetery | Cemetery | 323 | Wayne | 40 35 00 N | 093 22 26 W |
| Gregg Cemetery | Cemetery | 355 | Clarke | 40 54 49 N | 093 57 07 W |
| Gregg Cemetery | Cemetery | 229 | Jefferson | 41 00 28 N | 092 04 53 W |
| Gregg Post Office (historical) | Post Office | 257 | Johnson | 41 49 30 N | 091 44 06 W |
| Gregory Cemetery | Cemetery | 225 | Marion | 41 17 10 N | 092 52 51 W |
| Grell Pond | Reservoir | 399 | Ida | 42 22 22 N | 095 30 07 W |
| Grell Pond Dam | Dam | 400 | Ida | 42 22 24 N | 095 30 09 W |
| Gresham Cemetery | Cemetery | 307 | Black Hawk | 42 37 42 N | 092 13 14 W |
| Gresham Post Office (historical) | Post Office | 307 | Black Hawk | 42 37 40 N | 092 13 06 W |
| Gridley | Populated Place | 387 | Emmet | 43 23 58 N | 094 34 24 W |
| Gridley (historical) | Locale | 387 | Emmet | 43 23 58 N | 094 34 24 W |
| Gridley Post Office (historical) | Post Office | 387 | Emmet | 43 23 58 N | 094 34 24 W |
| Griebel School (historical) | School | 219 | Clinton | 41 50 38 N | 090 41 42 W |
| Griffen | Populated Place | 315 | Boone | 42 11 16 N | 093 47 42 W |
| Griffin Estate Cemetery | Cemetery | 251 | Jackson | 42 08 00 N | 090 52 21 W |
| Griffin Nursing Center | Hospital | 270 | Marion | 41 19 28 N | 093 05 31 W |
| Griffin Park | Park | 238 | Keokuk | 41 23 38 N | 092 21 11 W |
| Griffin Post Office (historical) | Post Office | 314 | Boone | 42 11 20 N | 093 47 41 W |
| Griffinsville | Locale | 296 | Appanoose | 40 50 38 N | 093 00 53 W |
| Griffinsville Post Office (historical) | Post Office | 296 | Appanoose | 40 50 38 N | 093 00 53 W |
| Griffis Cemetery | Cemetery | 273 | Jasper | 41 31 32 N | 093 12 52 W |
| Griffith Cemetery | Cemetery | 292 | Clayton | 42 40 60 N | 091 07 00 W |
| Griffith Cemetery | Cemetery | 237 | Wapello | 41 06 40 N | 092 31 01 W |
| Grim Cemetery | Cemetery | 221 | Louisa | 41 13 45 N | 091 17 49 W |
| Grimes | Locale | 293 | Polk | 41 41 15 N | 093 47 33 W |
| Grimes | Populated Place | 291 | Polk | 41 41 18 N | 093 47 28 W |
| Grimes Cemetery | Cemetery | 310 | Lucas | 41 01 45 N | 093 24 11 W |
| Grimes City Fire Station | Building | 291 | Polk | 41 41 14 N | 093 47 24 W |
| Grimes City Hall | Building | 291 | Polk | 41 41 14 N | 093 47 24 W |
| Grimes City Park | Park | 281 | Polk | 41 41 30 N | 093 47 06 W |
| Grimes Conservation Farm | Locale | 282 | Marshall | 42 03 00 N | 092 58 01 W |
| Grimes Family Care Center | Hospital | 286 | Polk | 41 41 20 N | 093 47 18 W |
| Grimes Jehovah's Witnesses Congregation | Church | 293 | Polk | 41 39 32 N | 093 45 31 W |
| Grimes Post Office | Post Office | 292 | Polk | 41 41 14 N | 093 47 26 W |
| Grimes Public Library | Building | 291 | Polk | 41 41 23 N | 093 47 39 W |
| Grimes School | School | 211 | Des Moines | 40 47 48 N | 091 06 26 W |
| Grimes School | School | 292 | Polk | 41 41 05 N | 093 47 30 W |
| Grinnell | Locale | 310 | Poweshiek | 41 44 30 N | 092 43 36 W |
| Grinnell | Populated Place | 309 | Poweshiek | 41 44 35 N | 092 43 21 W |
| Grinnell Area Christian Church | Church | 311 | Poweshiek | 41 44 47 N | 092 44 38 W |
| Grinnell Area Christian School | School | 311 | Poweshiek | 41 44 47 N | 092 44 38 W |
| Grinnell College | School | 311 | Poweshiek | 41 44 55 N | 092 43 13 W |
| Grinnell Country Club | Locale | 308 | Poweshiek | 41 45 23 N | 092 43 23 W |
| Grinnell East Bound Rest Area | Locale | 291 | Jasper | 41 41 40 N | 092 46 26 W |
| Grinnell Eye Care | Hospital | 311 | Poweshiek | 41 44 40 N | 092 43 38 W |
| Grinnell Family Care | Hospital | 308 | Poweshiek | 41 44 37 N | 092 44 02 W |
| Grinnell Fire Department | Building | 310 | Poweshiek | 41 44 37 N | 092 43 42 W |
| Grinnell High School | School | 310 | Poweshiek | 41 45 02 N | 092 44 19 W |
| Grinnell Historical Museum | Building | 310 | Poweshiek | 41 44 51 N | 092 43 29 W |
| Grinnell House | Building | 310 | Poweshiek | 41 44 43 N | 092 43 22 W |
| Grinnell Medical Associates | Hospital | 308 | Poweshiek | 41 44 34 N | 092 44 03 W |
| Grinnell Police Department | Building | 310 | Poweshiek | 41 44 37 N | 092 43 42 W |
| Grinnell Post Office | Post Office | 312 | Poweshiek | 41 44 40 N | 092 43 26 W |
| Grinnell Regional Airport | Airport | 305 | Poweshiek | 41 42 33 N | 092 44 06 W |
| Grinnell Regional Medical Center | Hospital | 308 | Poweshiek | 41 44 34 N | 092 44 03 W |
| Grinnell West Bound Rest Area | Locale | 288 | Jasper | 41 41 46 N | 092 46 22 W |
| Gripple's Quarry Bridge | Bridge | 191 | Louisa | 41 12 17 N | 091 24 32 W |
| Grismore Airport | Airport | 322 | Wayne | 40 46 00 N | 093 18 01 W |
| Griswold | Populated Place | 335 | Cass | 41 14 06 N | 095 08 15 W |
| Griswold (historical) | Locale | 335 | Cass | 41 14 02 N | 095 08 21 W |
| Griswold Care Center | Hospital | 336 | Cass | 41 14 12 N | 095 08 02 W |
| Griswold Cemetery | Cemetery | 217 | Louisa | 41 11 00 N | 091 19 01 W |
| Griswold Cemetery | Cemetery | 373 | Pottawattamie | 41 14 10 N | 095 10 26 W |
| Griswold City Hall | Building | 336 | Cass | 41 14 05 N | 095 08 36 W |
| Griswold Country Club | Locale | 352 | Cass | 41 14 55 N | 095 07 16 W |
| Griswold Elevator | Locale | 335 | Cass | 41 14 06 N | 095 08 15 W |
| Griswold High School | School | 336 | Cass | 41 14 23 N | 095 08 06 W |
| Griswold Park | Park | 337 | Cass | 41 15 16 N | 095 08 08 W |
| Griswold Police Department | Building | 335 | Cass | 41 14 06 N | 095 08 15 W |
| Griswold Post Office | Post Office | 336 | Cass | 41 14 05 N | 095 08 36 W |
| Griswold Public Library | Building | 335 | Cass | 41 13 58 N | 095 08 15 W |
| Gritter Creek | Stream | | Iowa | 41 32 02 N | 092 04 52 W |
| Groesbeck Cemetery | Cemetery | 364 | Union | 41 06 38 N | 094 07 26 W |
| Groesbeck County Wildlife Area | Park | 348 | Union | 41 05 48 N | 094 08 26 W |
| Groom Area | Park | 350 | Wright | 42 41 60 N | 093 32 06 W |
| Grossman Hall | Building | 282 | Bremer | 42 43 45 N | 092 28 51 W |
| Groth's Gardens | Locale | 325 | Madison | 41 23 15 N | 093 57 56 W |
| Grotto of the Redemption | Locale | 363 | Palo Alto | 42 57 54 N | 094 26 41 W |
| Grotto of the Redemption Campground | Locale | 364 | Palo Alto | 42 57 51 N | 094 26 47 W |
| Ground Mound Ball Park | Park | 216 | Clinton | 41 49 17 N | 090 38 49 W |
| Grout Cemetery | Cemetery | 218 | Johnson | 41 32 25 N | 091 38 12 W |
| Grout Museum of History and Science | Building | 263 | Black Hawk | 42 29 34 N | 092 20 39 W |
| Grout School | School | 262 | Black Hawk | 42 29 50 N | 092 18 31 W |
| Grove Branch Ditch | Canal | 323 | Hamilton | 42 21 07 N | 093 43 18 W |
| Grove Cemetery | Cemetery | 440 | Audubon | 41 32 46 N | 094 47 42 W |
| Grove Cemetery | Cemetery | 339 | Page | 40 37 33 N | 095 08 29 W |
| Grove Cemetery | Cemetery | 373 | Taylor | 40 51 20 N | 094 38 39 W |
| Grove Center Cemetery | Cemetery | 404 | Adair | 41 23 21 N | 094 24 58 W |
| Grove Center Church | Church | 409 | Adair | 41 22 54 N | 094 24 53 W |
| Grove Chapel Cemetery | Cemetery | 380 | Union | 40 56 07 N | 094 23 39 W |
| Grove City (historical) | Populated Place | 366 | Cass | 41 23 14 N | 094 57 44 W |
| Grove City Post Office (historical) | Post Office | 366 | Cass | 41 23 14 N | 094 57 44 W |
| Grove Creek | Stream | | Delaware | 42 16 55 N | 091 16 28 W |
| Grove Creek Cemetery | Cemetery | 275 | Delaware | 42 18 05 N | 091 18 54 W |
| Grove Creek Post Office (historical) | Post Office | 276 | Delaware | 42 18 00 N | 091 18 56 W |
| Grove Hill | Locale | 295 | Bremer | 42 40 55 N | 092 08 27 W |
| Grove Hill Cemetery | Cemetery | 312 | Bremer | 42 42 55 N | 092 08 46 W |
| Grove Hill Post Office (historical) | Post Office | 302 | Bremer | 42 41 36 N | 092 08 26 W |
| Grove Park | Park | 370 | Adams | 40 59 32 N | 094 44 16 W |
| Grove Post Office (historical) | Post Office | 397 | Audubon | 41 32 20 N | 094 49 39 W |
| Grove Post Office (historical) | Post Office | 298 | Marshall | 42 08 52 N | 093 08 59 W |
| Grove School | School | 314 | Lucas | 41 01 57 N | 093 18 08 W |
| Grove School | School | 314 | Lucas | 41 01 58 N | 093 18 08 W |
| Grove Township Cemetery | Cemetery | 372 | Shelby | 41 50 05 N | 095 32 14 W |
| Groveland (historical) | Locale | 354 | Clarke | 40 59 04 N | 093 47 54 W |
| Groveland (historical) | Populated Place | 354 | Clarke | 40 59 04 N | 093 47 54 W |
| Groveland Post Office (historical) | Post Office | 415 | Adair | 41 21 30 N | 094 25 60 W |
| Groveland Post Office (historical) | Post Office | 354 | Clarke | 40 59 04 N | 093 47 54 W |
| Grover Plot | Cemetery | 231 | Allamakee | 43 08 00 N | 091 11 00 W |
| Grovers Lake | Lake | 431 | Dickinson | 43 29 54 N | 095 09 28 W |