Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Oak Hill School (historical) | School | 279 | Dodge | 43 29 31 N | 088 58 45 W |
| Oak Hill School (historical) | School | 311 | Dunn | 44 55 27 N | 091 40 16 W |
| Oak Hill School (historical) | School | 339 | Portage | 44 35 26 N | 089 42 45 W |
| Oak Hill School (historical) | School | 324 | Sauk | 43 33 45 N | 090 05 29 W |
| Oak Hill School (historical) | School | 295 | St. Croix | 45 02 59 N | 092 34 50 W |
| Oak Island | Island | 308 | Ashland | 46 56 14 N | 090 43 42 W |
| Oak Island Park | Park | 357 | Marathon | 44 57 03 N | 089 37 50 W |
| Oak Island Shoal | Bar | 184 | Ashland | 46 58 33 N | 090 43 49 W |
| Oak Knoll | Populated Place | 268 | Dane | 42 56 34 N | 089 13 07 W |
| Oak Knoll | Populated Place | 252 | Waukesha | 42 52 07 N | 088 20 16 W |
| Oak Knoll Cemetery | Cemetery | 289 | Waukesha | 42 52 27 N | 088 28 46 W |
| Oak Knoll School | School | 346 | Washington | 43 23 28 N | 088 14 29 W |
| Oak Knoll School (historical) | School | 291 | Chippewa | 44 54 52 N | 091 37 50 W |
| Oak Knoll School (historical) | School | 311 | Eau Claire | 44 50 34 N | 091 14 48 W |
| Oak Knoll School (historical) | School | 325 | Polk | 45 13 29 N | 092 39 05 W |
| Oak Knoll School (historical) | School | 281 | St. Croix | 44 51 47 N | 092 39 52 W |
| Oak Lake | Lake | 301 | Burnett | 45 56 09 N | 092 07 57 W |
| Oak Lake | Lake | 497 | Forest | 45 28 31 N | 088 56 11 W |
| Oak Lake | Lake | 498 | Iron | 46 17 09 N | 089 59 56 W |
| Oak Lake | Lake | 446 | Lincoln | 45 16 28 N | 089 36 45 W |
| Oak Lake | Lake | 388 | Washburn | 45 46 60 N | 091 46 14 W |
| Oak Lake | Lake | 293 | Washburn | 46 01 10 N | 092 01 46 W |
| Oak Lawn Cemetery | Cemetery | 286 | Dane | 43 15 13 N | 089 05 18 W |
| Oak Lawn Cemetery | Cemetery | 259 | Marquette | 43 43 23 N | 089 21 07 W |
| Oak Lawn Cemetery | Cemetery | 312 | Sauk | 43 35 29 N | 090 08 08 W |
| Oak Lawn School | School | 289 | Dodge | 43 35 47 N | 088 46 30 W |
| Oak Lawn School (historical) | School | 287 | Dane | 43 15 14 N | 089 05 16 W |
| Oak Lawn School (historical) | School | 306 | Dunn | 45 08 04 N | 092 01 24 W |
| Oak Lawn School (historical) | School | 253 | Fond du Lac | 43 52 11 N | 088 52 13 W |
| Oak Lawn School (historical) | School | 305 | Polk | 45 13 27 N | 092 42 44 W |
| Oak Leaf School (historical) | School | 265 | Outagamie | 44 33 07 N | 088 22 05 W |
| Oak Leaf School (historical) | School | 357 | Wood | 44 32 52 N | 090 10 50 W |
| Oak Mound Cemetery | Cemetery | 294 | Fond du Lac | 43 41 21 N | 088 47 52 W |
| Oak Orchard | Populated Place | 178 | Oconto | 44 46 53 N | 087 55 33 W |
| Oak Park | Locale | 267 | Dane | 43 04 42 N | 089 06 20 W |
| Oak Park | Park | 276 | Sauk | 43 32 15 N | 089 59 52 W |
| Oak Park School | School | 277 | Dane | 43 05 14 N | 089 06 36 W |
| Oak Park School | School | 332 | Iowa | 42 50 08 N | 090 13 27 W |
| Oak Park School | School | 264 | Shawano | 44 50 10 N | 088 36 07 W |
| Oak Point | Cape | 184 | Ashland | 46 39 40 N | 090 45 41 W |
| Oak Ridge | Ridge | 319 | Crawford | 43 17 13 N | 091 01 42 W |
| Oak Ridge | Ridge | 338 | Grant | 43 09 08 N | 090 33 21 W |
| Oak Ridge | Ridge | 334 | Richland | 43 16 07 N | 090 24 59 W |
| Oak Ridge | Ridge | 396 | Trempealeau | 44 11 36 N | 091 23 34 W |
| Oak Ridge | Ridge | 359 | Vernon | 43 37 38 N | 091 10 42 W |
| Oak Ridge Cemetery | Cemetery | 323 | Grant | 42 50 19 N | 090 33 55 W |
| Oak Ridge Cemetery | Cemetery | 373 | Pierce | 44 49 51 N | 092 09 23 W |
| Oak Ridge Cemetery | Cemetery | 318 | Richland | 43 15 47 N | 090 24 44 W |
| Oak Ridge Cemetery | Cemetery | 261 | Walworth | 42 47 35 N | 088 23 29 W |
| Oak Ridge Cemetery | Cemetery | 286 | Waukesha | 42 52 26 N | 088 28 55 W |
| Oak Ridge Church | Church | 399 | Vernon | 43 42 29 N | 090 42 35 W |
| Oak Ridge Farm | Locale | 363 | Richland | 43 30 17 N | 090 26 32 W |
| Oak Ridge Fire Tower | Tower | 369 | Jackson | 44 12 49 N | 090 43 21 W |
| Oak Ridge Holstein Farm | Locale | 314 | Richland | 43 15 33 N | 090 25 13 W |
| Oak Ridge Lake | Lake | 305 | St. Croix | 45 11 06 N | 092 28 41 W |
| Oak Ridge Lutheran Church | Church | 262 | Dunn | 44 51 38 N | 091 56 09 W |
| Oak Ridge Park | Park | 271 | Jefferson | 43 00 36 N | 088 48 07 W |
| Oak Ridge School | School | 243 | Grant | 42 44 02 N | 090 50 16 W |
| Oak Ridge School | School | 289 | Jackson | 44 13 42 N | 090 45 50 W |
| Oak Ridge School (historical) | School | 335 | Crawford | 43 22 48 N | 091 06 06 W |
| Oak Ridge School (historical) | School | 329 | Dunn | 45 04 31 N | 092 05 10 W |
| Oak Ridge School (historical) | School | 315 | Eau Claire | 44 46 17 N | 091 08 19 W |
| Oak Ridge School (historical) | School | 243 | Marinette | 45 10 57 N | 088 03 46 W |
| Oak Ridge School (historical) | School | 330 | Richland | 43 14 55 N | 090 24 18 W |
| Oak Ridge School (historical) | School | 267 | St. Croix | 44 54 44 N | 092 43 54 W |
| Oak Ridge School (historical) | School | 406 | Trempealeau | 44 11 32 N | 091 22 03 W |
| Oak Ridge School (historical) | School | 360 | Vernon | 43 37 35 N | 091 10 44 W |
| Oak School (historical) | School | 265 | Juneau | 43 47 56 N | 089 56 18 W |
| Oak School (historical) | School | 250 | Oconto | 44 59 50 N | 088 13 28 W |
| Oak Street Dam | Dam | 255 | Sauk | 43 27 60 N | 089 44 42 W |
| Oak Street Park | Park | 262 | Dane | 43 06 07 N | 089 20 32 W |
| Oak Valley | Valley | | Buffalo | 44 13 25 N | 091 43 58 W |
| Oak Valley School (historical) | School | 207 | Buffalo | 44 13 05 N | 091 45 09 W |
| Oak Valley School (historical) | School | 323 | St. Croix | 44 56 47 N | 092 35 47 W |
| Oak View Farm | Locale | 324 | Richland | 43 21 37 N | 090 27 26 W |
| Oak View School | School | 273 | Sauk | 43 21 24 N | 090 04 10 W |
| Oak View School (historical) | School | 349 | Polk | 45 16 44 N | 092 19 03 W |
| Oak View School (historical) | School | 332 | Rusk | 45 20 06 N | 091 02 56 W |
| Oakbrook Airport | Airport | 252 | Jefferson | 42 53 24 N | 088 48 29 W |
| Oakbrook Shopping Center | Locale | 214 | Milwaukee | 42 52 17 N | 087 54 50 W |
| Oakdale | Populated Place | 293 | Monroe | 43 57 35 N | 090 22 54 W |
| Oakdale Cemetery | Cemetery | 305 | Monroe | 43 56 45 N | 090 23 38 W |
| Oakdale Elementary School | School | 295 | Monroe | 43 57 29 N | 090 22 49 W |
| Oakdale Park | Park | 184 | Brown | 44 29 50 N | 087 58 36 W |
| Oakdale School | School | 347 | Jackson | 44 13 55 N | 090 33 15 W |
| Oakdale School | School | 262 | Rock | 42 47 23 N | 089 00 50 W |
| Oakdale School | School | 261 | Waukesha | 42 57 08 N | 088 15 38 W |
| Oakdale School (historical) | School | 369 | St. Croix | 45 04 39 N | 092 18 38 W |
| Oakdale School (historical) | School | 263 | Trempealeau | 44 15 45 N | 091 23 06 W |
| Oakfield | Populated Place | 271 | Fond du Lac | 43 41 10 N | 088 32 47 W |
| Oakfield High School | School | 275 | Fond du Lac | 43 41 07 N | 088 32 30 W |
| Oakfield Ledge State Natural Area | Park | 44 | Fond du Lac | 43 40 25 N | 088 33 13 W |
| Oakfield Railroad Prairie State Natural Area | Park | 44 | Fond du Lac | 43 43 03 N | 088 30 21 W |
| Oakfield United Methodist Church | Church | 279 | Fond du Lac | 43 40 53 N | 088 32 52 W |
| Oakhaven Church | Church | 235 | Winnebago | 44 01 04 N | 088 35 08 W |
| Oakhill Correctional Institution | Locale | 302 | Dane | 42 57 41 N | 089 23 35 W |
| Oakhurst School (historical) | School | 229 | La Crosse | 43 50 59 N | 091 08 15 W |
| Oakland | Populated Place | 298 | Burnett | 45 56 15 N | 092 22 08 W |
| Oakland | Populated Place | 267 | Jefferson | 42 58 36 N | 088 57 20 W |
| Oakland 3 WR 1801 Dam | Dam | 254 | Jefferson | 43 00 00 N | 088 58 12 W |
| Oakland Cemetery | Cemetery | 308 | Burnett | 45 57 08 N | 092 18 60 W |
| Oakland Cemetery | Cemetery | 333 | Chippewa | 44 57 21 N | 090 55 29 W |
| Oakland Cemetery | Cemetery | 263 | Pepin | 44 29 32 N | 092 15 32 W |
| Oakland Cemetery | Cemetery | 298 | St. Croix | 45 10 38 N | 092 32 53 W |
| Oakland Church | Church | 324 | Douglas | 46 31 56 N | 091 59 35 W |
| Oakland Farm | Locale | 376 | Richland | 43 27 23 N | 090 36 45 W |
| Oakland Farm | Locale | 234 | Richland | 43 31 47 N | 090 39 38 W |
| Oakland Farm | Locale | 322 | Richland | 43 18 05 N | 090 26 37 W |
| Oakland Heights | Populated Place | 261 | Dane | 43 03 58 N | 089 24 43 W |
| Oakland School | School | 321 | Douglas | 46 31 55 N | 092 01 24 W |