Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Jacques Elementary School | School | 323 | Greene | 42 00 27 N | 094 22 10 W |
| Jaggar Cemetery | Cemetery | 216 | Des Moines | 40 51 23 N | 091 20 46 W |
| Jakway Forest County Park | Park | 329 | Buchanan | 42 35 30 N | 091 44 11 W |
| Jamaica | Populated Place | 315 | Guthrie | 41 50 46 N | 094 18 35 W |
| Jamaica (historical) | Locale | 318 | Guthrie | 41 50 41 N | 094 18 26 W |
| Jamaica City Hall | Building | 315 | Guthrie | 41 50 46 N | 094 18 35 W |
| Jamaica Library | Building | 315 | Guthrie | 41 50 46 N | 094 18 35 W |
| Jamaica Post Office | Post Office | 315 | Guthrie | 41 50 46 N | 094 18 35 W |
| Jamaica Union Church | Church | 317 | Guthrie | 41 50 45 N | 094 18 21 W |
| James | Locale | 344 | Plymouth | 42 34 37 N | 096 18 56 W |
| James | Populated Place | 346 | Plymouth | 42 34 37 N | 096 19 03 W |
| James 'Tame Jim' Wilson State Historical Marker | Park | 292 | Tama | 42 11 26 N | 092 27 52 W |
| James A Throop Home Historical Marker | Park | 208 | Henry | 40 57 40 N | 091 33 41 W |
| James and Sharon Walker Science Center | Building | 386 | Woodbury | 42 28 23 N | 096 21 30 W |
| James Elementary School | School | 244 | Wapello | 41 01 56 N | 092 25 15 W |
| James Gildea Cemetery | Cemetery | 310 | Boone | 41 58 20 N | 093 52 51 W |
| James Harlan State Historical Marker | Park | 223 | Henry | 40 57 58 N | 091 33 14 W |
| James Miller Park | Park | 308 | Poweshiek | 41 44 05 N | 092 43 10 W |
| James Post Office (historical) | Post Office | 346 | Plymouth | 42 34 37 N | 096 19 03 W |
| James Residence Hall | Building | 311 | Poweshiek | 41 44 53 N | 092 43 03 W |
| James Wilson Grimes Homesite Historical Marker | Park | 211 | Des Moines | 40 47 48 N | 091 06 27 W |
| Jamestown | Populated Place | 259 | Keokuk | 41 25 45 N | 092 21 18 W |
| Jamestown | Populated Place | 229 | Scott | 41 29 40 N | 090 42 30 W |
| Jamestown Highway Rest Area | Locale | 395 | Howard | 43 21 50 N | 092 30 09 W |
| Jamestown Post Office (historical) | Post Office | 229 | Scott | 41 29 40 N | 090 42 30 W |
| Jamestown Post Office (historical) | Post Office | 370 | Winneshiek | 43 14 05 N | 091 36 21 W |
| Jamison | Populated Place | 295 | Clarke | 41 07 18 N | 093 43 30 W |
| Jamison (historical) | Locale | 295 | Clarke | 41 07 18 N | 093 43 30 W |
| Jamison Cemetery | Cemetery | 316 | Clarke | 41 07 34 N | 093 43 34 W |
| Jamison Post Office (historical) | Post Office | 295 | Clarke | 41 07 18 N | 093 43 30 W |
| Jana Recreation Area | Park | 353 | Sac | 42 19 20 N | 094 57 26 W |
| Jane Lamb Health Center | Hospital | 196 | Clinton | 41 50 24 N | 090 12 57 W |
| Jane Springer Sports Field | Park | 308 | Poweshiek | 41 45 10 N | 092 43 12 W |
| Janesville | Locale | 272 | Bremer | 42 38 38 N | 092 27 32 W |
| Janesville | Populated Place | 276 | Bremer | 42 38 46 N | 092 27 47 W |
| Janesville City Hall | Building | 277 | Bremer | 42 38 52 N | 092 27 49 W |
| Janesville City Library | Building | 277 | Bremer | 42 38 54 N | 092 27 49 W |
| Janesville City Park | Park | 276 | Bremer | 42 38 46 N | 092 27 47 W |
| Janesville Fire Department | Building | 277 | Bremer | 42 38 52 N | 092 27 49 W |
| Janesville Police Department | Building | 277 | Bremer | 42 38 52 N | 092 27 49 W |
| Janesville Post Office | Post Office | 276 | Bremer | 42 38 46 N | 092 27 47 W |
| Janesville Public School | School | 284 | Bremer | 42 38 60 N | 092 27 32 W |
| Japan Slough | Channel | 187 | Allamakee | 43 10 20 N | 091 09 17 W |
| Jasper County | Civil | 271 | Jasper | 41 41 00 N | 093 03 01 W |
| Jasper County Burying Ground | Cemetery | 275 | Jasper | 41 40 40 N | 092 59 51 W |
| Jasper County Courthouse | Building | 292 | Jasper | 41 41 60 N | 093 03 16 W |
| Jasper County Historical Museum | Building | 264 | Jasper | 41 41 10 N | 093 04 31 W |
| Jasper County Home | Building | 283 | Jasper | 41 40 41 N | 092 59 23 W |
| Jasper County Sheriffs Office | Building | 292 | Jasper | 41 41 60 N | 093 03 16 W |
| Jasper Post Office (historical) | Post Office | 330 | Carroll | 42 10 04 N | 094 42 38 W |
| Jay | Populated Place | 324 | Clarke | 41 06 24 N | 093 35 12 W |
| Jay Cemetery | Cemetery | 240 | Davis | 40 49 44 N | 092 19 23 W |
| Jay Cemetery | Cemetery | 273 | Wapello | 40 54 47 N | 092 36 40 W |
| Jay G Sigmund Park | Park | 244 | Linn | 42 09 55 N | 091 27 37 W |
| Jay Park | Park | 221 | Linn | 41 57 47 N | 091 40 01 W |
| Jay Post Office (historical) | Post Office | 324 | Clarke | 41 06 24 N | 093 35 12 W |
| Jaycee Park | Park | 260 | Marion | 41 25 25 N | 092 55 06 W |
| Jaycee Park | Park | 291 | Polk | 41 35 45 N | 093 47 06 W |
| Jaycee Park | Park | 305 | Poweshiek | 41 44 28 N | 092 42 50 W |
| JayCee Park | Park | 377 | Shelby | 41 38 52 N | 095 19 13 W |
| Jaycee Park | Park | 437 | Sioux | 43 00 02 N | 096 03 23 W |
| Jaycee Park | Park | 337 | Wright | 42 39 36 N | 093 53 54 W |
| Jaycees Park | Park | 305 | Marshall | 42 00 34 N | 092 56 08 W |
| Jeddo City | Locale | 354 | Harrison | 41 41 00 N | 095 40 31 W |
| Jeddo City Post Office (historical) | Post Office | 346 | Harrison | 41 40 30 N | 095 40 31 W |
| Jeff (historical) | Locale | 320 | Fayette | 42 41 60 N | 091 56 26 W |
| Jeffers Campground | Locale | 369 | Woodbury | 42 32 37 N | 096 25 52 W |
| Jefferson | Locale | 220 | Clayton | 42 40 10 N | 091 07 31 W |
| Jefferson | Locale | 321 | Greene | 42 01 18 N | 094 22 41 W |
| Jefferson | Populated Place | 325 | Greene | 42 00 55 N | 094 22 39 W |
| Jefferson Building | Building | 209 | Johnson | 41 39 35 N | 091 32 01 W |
| Jefferson Cemetery | Cemetery | 376 | Adair | 41 27 40 N | 094 25 16 W |
| Jefferson Cemetery | Cemetery | 297 | Black Hawk | 42 39 25 N | 092 19 57 W |
| Jefferson Cemetery | Cemetery | 297 | Bremer | 42 39 25 N | 092 19 57 W |
| Jefferson Cemetery | Cemetery | 325 | Greene | 42 00 48 N | 094 21 34 W |
| Jefferson Cemetery | Cemetery | 304 | Madison | 41 26 06 N | 093 55 10 W |
| Jefferson Center Church | Church | 391 | Adair | 41 27 38 N | 094 23 43 W |
| Jefferson Church | Church | 303 | Madison | 41 26 05 N | 093 55 09 W |
| Jefferson City Hall | Building | 326 | Greene | 42 01 02 N | 094 22 29 W |
| Jefferson Clinic | Hospital | 347 | Guthrie | 41 51 07 N | 094 33 30 W |
| Jefferson County | Civil | 234 | Jefferson | 41 02 00 N | 091 57 01 W |
| Jefferson County Courthouse | Building | 235 | Jefferson | 41 00 33 N | 091 57 48 W |
| Jefferson County Fairgrounds | Locale | 232 | Jefferson | 41 00 30 N | 091 59 41 W |
| Jefferson County Home | Building | 228 | Jefferson | 40 56 37 N | 091 59 59 W |
| Jefferson County Hospital | Hospital | 233 | Jefferson | 41 00 14 N | 091 57 11 W |
| Jefferson County Law Enforcement Center | Building | 232 | Jefferson | 41 00 35 N | 091 58 43 W |
| Jefferson County Park | Park | 211 | Jefferson | 40 59 20 N | 091 59 13 W |
| Jefferson County Park Trail | Trail | 211 | Jefferson | 40 59 20 N | 091 59 13 W |
| Jefferson Elementary School | School | 401 | Clay | 43 08 55 N | 095 08 19 W |
| Jefferson Elementary School | School | 180 | Clinton | 41 50 39 N | 090 12 10 W |
| Jefferson Elementary School | School | 262 | Marion | 41 24 25 N | 092 53 56 W |
| Jefferson Elementary School | School | 184 | Muscatine | 41 25 45 N | 091 02 54 W |
| Jefferson Eye Care Center | Hospital | 328 | Greene | 42 00 55 N | 094 22 26 W |
| Jefferson Fire Station | Building | 324 | Greene | 42 01 02 N | 094 22 26 W |
| Jefferson Healthcare Center | Hospital | 324 | Greene | 42 00 07 N | 094 22 32 W |
| Jefferson High School | School | 251 | Linn | 41 57 55 N | 091 41 56 W |
| Jefferson High School | School | 299 | Pottawattamie | 41 15 42 N | 095 52 59 W |
| Jefferson Middle School | School | 324 | Greene | 42 00 50 N | 094 22 36 W |
| Jefferson Municipal Airport | Airport | 317 | Greene | 42 00 37 N | 094 20 32 W |
| Jefferson Park | Park | 207 | Scott | 41 31 50 N | 090 35 12 W |
| Jefferson Park | Park | 197 | Wapello | 40 59 25 N | 092 24 56 W |
| Jefferson Park | Park | 335 | Woodbury | 42 24 30 N | 096 21 51 W |
| Jefferson Post Office | Post Office | 325 | Greene | 42 00 52 N | 094 22 33 W |
| Jefferson Post Office (historical) | Post Office | 293 | Davis | 40 39 14 N | 092 35 14 W |
| Jefferson Public Library | Building | 326 | Greene | 42 00 57 N | 094 22 35 W |
| Jefferson School | School | 334 | Cerro Gordo | 43 08 51 N | 093 10 26 W |
| Jefferson School | School | 230 | Dubuque | 42 31 16 N | 090 39 51 W |
| Jefferson School | School | 317 | Floyd | 43 03 22 N | 092 41 02 W |
| Jefferson School | School | 198 | Lee | 40 24 29 N | 091 24 01 W |
| Jefferson School | School | 166 | Lee | 40 37 54 N | 091 20 19 W |