Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Lyons (historical) | Park | 390 | Shelby | 41 34 06 N | 095 05 20 W |
| Lyons Branch Library | Building | 180 | Clinton | 41 52 18 N | 090 10 44 W |
| Lyons Cemetery | Cemetery | 312 | Appanoose | 40 46 46 N | 093 03 34 W |
| Lyons Chute | Stream | | Clinton | 41 53 15 N | 090 10 08 W |
| Lyons Creek | Stream | | Hamilton | 42 27 60 N | 093 48 38 W |
| Lyons Middle School | School | 205 | Clinton | 41 52 49 N | 090 11 04 W |
| Lyons Park | Park | 355 | Woodbury | 42 29 48 N | 096 26 11 W |
| Lyons Post Office (historical) | Post Office | 198 | Clinton | 41 52 02 N | 090 11 10 W |
| Lyons United Methodist Church | Church | 180 | Clinton | 41 52 12 N | 090 10 51 W |
| Lytle Cemetery | Cemetery | 379 | Harrison | 41 33 45 N | 095 33 19 W |
| Lytle Cemetery | Cemetery | 284 | Poweshiek | 41 39 09 N | 092 29 03 W |
| Lytle City (historical) | Locale | 229 | Iowa | 41 36 02 N | 091 57 01 W |
| Lytle City Post Office (historical) | Post Office | 244 | Iowa | 41 35 30 N | 091 57 21 W |
| Lytle Creek | Stream | | Jackson | 42 11 15 N | 090 45 07 W |
| Lytles Creek | Stream | | Harrison | 41 33 45 N | 095 34 16 W |
| Lytles Grove Cemetery | Cemetery | 371 | Union | 41 01 11 N | 094 25 56 W |
| Lytton | Populated Place | 374 | Calhoun | 42 25 23 N | 094 51 35 W |
| Lytton (historical) | Locale | 373 | Sac | 42 25 17 N | 094 51 34 W |
| Lytton City Hall | Building | 374 | Sac | 42 25 20 N | 094 51 36 W |
| Lytton Post Office | Post Office | 373 | Sac | 42 25 21 N | 094 51 31 W |
| Lytton Public Library | Building | 374 | Sac | 42 25 22 N | 094 51 36 W |
| M and M Country Club | Locale | 435 | Crawford | 41 54 16 N | 095 10 49 W |
| M and S Mobile Home Park | Populated Place | 331 | Boone | 42 02 40 N | 094 02 11 W |
| M C Community Library | Building | 445 | Cherokee | 42 48 44 N | 095 42 46 W |
| M L King Park | Park | 256 | Polk | 41 36 12 N | 093 35 33 W |
| M M Hoffman Public Library | Building | 293 | Dubuque | 42 29 05 N | 091 07 14 W |
| Maas Cemetery | Cemetery | 346 | Boone | 42 05 27 N | 094 03 44 W |
| Maas Cemetery | Cemetery | 223 | Iowa | 41 46 47 N | 091 56 56 W |
| Maas Cemetery | Cemetery | 223 | Iowa | 41 47 10 N | 091 59 02 W |
| Mac Coon County Park | Park | 181 | Jefferson | 41 03 05 N | 091 44 08 W |
| Mac Rae Park | Park | 267 | Polk | 41 34 01 N | 093 37 34 W |
| MacArthur Bridge | Bridge | 155 | Des Moines | 40 48 45 N | 091 05 51 W |
| MacBride Hall | Building | 212 | Johnson | 41 39 43 N | 091 32 08 W |
| MacCollin Classroom Building | Building | 375 | Woodbury | 42 28 23 N | 096 21 36 W |
| MacEachron Field | Park | 311 | Poweshiek | 41 45 01 N | 092 43 16 W |
| Macedonia | Populated Place | 340 | Pottawattamie | 41 11 34 N | 095 25 32 W |
| Macedonia (historical) | Locale | 340 | Pottawattamie | 41 11 34 N | 095 25 32 W |
| Macedonia Baptist Church | Church | 296 | Polk | 41 35 54 N | 093 39 35 W |
| Macedonia Cemetery | Cemetery | 352 | Pottawattamie | 41 11 32 N | 095 25 01 W |
| Macedonia City Hall | Building | 340 | Pottawattamie | 41 11 34 N | 095 25 32 W |
| Macedonia Post Office (historical) | Post Office | 329 | Pottawattamie | 41 11 39 N | 095 26 31 W |
| Maceville Post Office (historical) | Post Office | 270 | Lucas | 41 03 33 N | 093 09 31 W |
| Macey | Populated Place | 354 | Hardin | 42 32 22 N | 093 08 53 W |
| MacKay Hall | Building | 291 | Story | 42 01 42 N | 093 38 50 W |
| Mackey | Populated Place | 307 | Boone | 42 09 59 N | 093 45 25 W |
| Mackey Cemetery | Cemetery | 308 | Boone | 42 10 03 N | 093 45 24 W |
| Mackey Cemetery | Cemetery | 344 | Fremont | 40 54 05 N | 095 44 16 W |
| Mackey Cemetery | Cemetery | 308 | Mills | 40 54 30 N | 095 44 31 W |
| Mackey Post Office (historical) | Post Office | 307 | Boone | 42 09 59 N | 093 45 25 W |
| Mackey School (historical) | School | 307 | Boone | 42 09 59 N | 093 45 25 W |
| Mackin Grain Company Elevator | Locale | 308 | Marshall | 42 07 20 N | 093 11 42 W |
| Macks Post Office (historical) | Post Office | 371 | Carroll | 42 00 25 N | 094 48 21 W |
| Macksburg | Populated Place | 380 | Madison | 41 12 53 N | 094 11 07 W |
| Macksburg Post Office | Post Office | 380 | Madison | 41 12 50 N | 094 11 09 W |
| Macksburg United Methodist Church | Church | 380 | Madison | 41 12 50 N | 094 11 09 W |
| Maclay (historical) | Populated Place | 412 | Clay | 42 58 09 N | 095 04 23 W |
| MacLean Hall | Building | 211 | Johnson | 41 39 38 N | 091 32 11 W |
| MacNiders Woods | Park | 338 | Cerro Gordo | 43 09 23 N | 093 13 04 W |
| Macomb Park | Park | 374 | Woodbury | 42 28 48 N | 096 22 15 W |
| Macs Preserve | Park | 436 | Cherokee | 42 46 47 N | 095 41 59 W |
| Macy | Locale | 354 | Hardin | 42 32 22 N | 093 08 53 W |
| Macy Post Office (historical) | Post Office | 354 | Hardin | 42 32 22 N | 093 08 53 W |
| Mad Creek | Stream | | Muscatine | 41 25 27 N | 091 02 08 W |
| Mad Creek Greenbelt Park | Park | 185 | Muscatine | 41 27 11 N | 091 02 13 W |
| Mada Post Office (historical) | Post Office | 351 | Guthrie | 41 44 10 N | 094 36 41 W |
| Mades Hall | Building | 269 | Dubuque | 42 29 54 N | 090 41 35 W |
| Madison | Locale | 378 | Hancock | 43 10 07 N | 093 43 28 W |
| Madison (historical) | Locale | 275 | Jones | 42 03 50 N | 091 05 56 W |
| Madison Baptist Church | Church | 170 | Lee | 40 37 35 N | 091 22 01 W |
| Madison Cemetery | Cemetery | 348 | Buchanan | 42 35 23 N | 091 42 24 W |
| Madison Cemetery | Cemetery | 310 | Butler | 42 41 13 N | 092 58 03 W |
| Madison Cemetery | Cemetery | 372 | Hancock | 43 14 28 N | 093 38 15 W |
| Madison Cemetery | Cemetery | 242 | Mahaska | 41 21 28 N | 092 41 18 W |
| Madison Cemetery | Cemetery | 358 | Winneshiek | 43 18 49 N | 091 55 25 W |
| Madison Center Cemetery | Cemetery | 288 | Jones | 42 04 40 N | 091 04 33 W |
| Madison Chapel | Church | 355 | Clarke | 41 08 46 N | 093 58 01 W |
| Madison Church | Church | 287 | Poweshiek | 41 47 22 N | 092 30 50 W |
| Madison Church | Church | 358 | Winneshiek | 43 18 49 N | 091 55 25 W |
| Madison County | Civil | 342 | Madison | 41 20 00 N | 094 01 01 W |
| Madison County Courthouse | Building | 342 | Madison | 41 20 06 N | 094 00 50 W |
| Madison County Fairgrounds | Locale | 344 | Madison | 41 19 45 N | 094 01 46 W |
| Madison County Medical Associates Center | Hospital | 342 | Madison | 41 20 04 N | 094 00 51 W |
| Madison County Memorial Hospital | Hospital | 337 | Madison | 41 19 42 N | 094 01 01 W |
| Madison County Sheriffs Office | Building | 336 | Madison | 41 20 45 N | 094 00 51 W |
| Madison Junior High School | School | 215 | Des Moines | 40 47 08 N | 091 06 25 W |
| Madison Park | Park | 216 | Dubuque | 42 30 33 N | 090 40 14 W |
| Madison Post Office (historical) | Post Office | 275 | Jones | 42 03 50 N | 091 05 56 W |
| Madison School | School | 363 | Cerro Gordo | 43 07 37 N | 093 12 28 W |
| Madison School | School | 260 | Linn | 41 59 10 N | 091 42 38 W |
| Madison School | School | 185 | Muscatine | 41 26 42 N | 091 02 04 W |
| Madison School | School | 255 | Polk | 41 37 57 N | 093 36 29 W |
| Madison School | School | 350 | Pottawattamie | 41 15 26 N | 095 50 13 W |
| Madison School | School | 213 | Scott | 41 32 20 N | 090 34 25 W |
| Madison Settlement Cemetery | Cemetery | 357 | Winneshiek | 43 15 39 N | 091 55 25 W |
| Madison Shoppes | Locale | 300 | Pottawattamie | 41 14 05 N | 095 49 11 W |
| Madison Village Cemetery | Cemetery | 283 | Jones | 42 04 10 N | 091 06 11 W |
| Madrid | Locale | 305 | Boone | 41 52 28 N | 093 48 51 W |
| Madrid | Populated Place | 309 | Boone | 41 52 36 N | 093 49 24 W |
| Madrid Elementary School | School | 308 | Boone | 41 52 38 N | 093 49 20 W |
| Madrid Fire Station | Building | 307 | Boone | 41 52 29 N | 093 49 19 W |
| Madrid Home | Hospital | 310 | Boone | 41 52 42 N | 093 49 40 W |
| Madrid Junior and High School | School | 314 | Boone | 41 52 60 N | 093 48 51 W |
| Madrid Police Department | Building | 307 | Boone | 41 52 29 N | 093 49 19 W |
| Madrid Post Office | Post Office | 308 | Boone | 41 52 31 N | 093 49 24 W |
| Madrid Public Library | Building | 310 | Boone | 41 52 34 N | 093 49 15 W |
| Magee Lake | Lake | 155 | Des Moines | 40 42 41 N | 091 07 23 W |
| Magill | Populated Place | 373 | Harrison | 41 31 08 N | 095 30 20 W |
| Magnolia | Populated Place | 408 | Harrison | 41 41 45 N | 095 52 36 W |
| Magnolia Cemetery | Cemetery | 397 | Harrison | 41 41 25 N | 095 52 49 W |
| Magnolia Post Office (historical) | Post Office | 408 | Harrison | 41 41 45 N | 095 52 36 W |