Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Otter Creek Townhall | Building | 297 | Dunn | 45 06 14 N | 091 51 54 W |
| Otter Island | Island | 225 | Ashland | 46 59 46 N | 090 41 28 W |
| Otter Island | Island | 225 | Iowa | 43 11 51 N | 089 51 02 W |
| Otter Lake | Lake | 399 | Forest | 45 26 06 N | 088 31 39 W |
| Otter Lake | Lake | 480 | Iron | 46 01 37 N | 090 11 01 W |
| Otter Lake | Lake | 500 | Iron | 46 18 13 N | 089 59 13 W |
| Otter Lake | Lake | 494 | Langlade | 45 26 39 N | 089 11 11 W |
| Otter Lake | Lake | 516 | Langlade | 45 26 50 N | 089 25 16 W |
| Otter Lake | Lake | 496 | Lincoln | 45 26 30 N | 089 32 38 W |
| Otter Lake | Lake | 255 | Marinette | 45 39 57 N | 087 53 22 W |
| Otter Lake | Lake | 493 | Vilas | 45 56 34 N | 089 13 18 W |
| Otter Lake | Lake | 417 | Washburn | 45 45 15 N | 091 32 53 W |
| Otter Lake | Lake | 271 | Waupaca | 44 20 52 N | 089 08 25 W |
| Otter Lake | Reservoir | 347 | Chippewa | 45 05 26 N | 090 57 11 W |
| Otter Lake 27 | Reservoir | 348 | Chippewa | 45 05 18 N | 090 57 12 W |
| Otter Lake 2WP315 Dam | Dam | 347 | Chippewa | 45 05 26 N | 090 57 11 W |
| Otter Lake Recreation Area | Park | 500 | Lincoln | 45 26 16 N | 089 32 36 W |
| Otter Pond | Lake | 286 | Sheboygan | 43 47 54 N | 088 01 55 W |
| Otter Rapids 1905c483 Dam | Dam | 493 | Vilas | 45 54 12 N | 089 19 12 W |
| Otter Rapids Dam | Dam | 493 | Vilas | 45 54 12 N | 089 19 13 W |
| Otter Rapids Golf Course | Locale | 494 | Vilas | 45 54 30 N | 089 22 20 W |
| Otter Slide Rapids | Rapids | 394 | Rusk | 45 37 28 N | 090 46 04 W |
| Otter Springs | Spring | 486 | Forest | 45 35 04 N | 088 48 42 W |
| Otterholt Cemetery | Cemetery | 334 | Barron | 45 18 56 N | 091 43 35 W |
| Otterholt School (historical) | School | 337 | Barron | 45 19 20 N | 091 43 32 W |
| Ottertail Creek | Stream | | Price | 45 29 08 N | 090 21 12 W |
| Ottertail Springs | Spring | 450 | Price | 45 28 53 N | 090 18 24 W |
| Ottervale Church | Church | 276 | Vernon | 43 35 30 N | 090 41 42 W |
| Ottervale School (historical) | School | 269 | Vernon | 43 35 27 N | 090 41 25 W |
| Otteson Bluff | Summit | 380 | Dunn | 44 58 03 N | 091 54 33 W |
| Ottman Corners | Populated Place | 313 | Pierce | 44 42 12 N | 092 31 02 W |
| Ottman Lake | Lake | 271 | Waupaca | 44 20 07 N | 089 10 36 W |
| Otto Tank Park | Park | 179 | Brown | 44 31 41 N | 088 02 02 W |
| Otto-Gibbons Airport | Airport | 258 | Brown | 44 16 40 N | 087 56 40 W |
| Otts Park | Park | 385 | Lincoln | 45 10 57 N | 089 43 11 W |
| Ottumba Park | Park | 176 | Door | 44 49 50 N | 087 23 19 W |
| Oula Pioneer Memorial Park | Park | 305 | Bayfield | 46 37 16 N | 091 26 46 W |
| Oulu | Populated Place | 303 | Bayfield | 46 37 59 N | 091 31 55 W |
| Oulu Cemetery | Cemetery | 284 | Bayfield | 46 39 18 N | 091 31 56 W |
| Oulu Church | Church | 311 | Bayfield | 46 36 20 N | 091 26 51 W |
| Oulu Church | Church | 295 | Bayfield | 46 38 39 N | 091 31 53 W |
| Oulu School | School | 325 | Bayfield | 46 37 07 N | 091 29 43 W |
| Oulu Townhall | Building | 323 | Bayfield | 46 37 08 N | 091 31 32 W |
| Ounce River | Stream | | Douglas | 46 10 05 N | 091 41 38 W |
| Our Fathers Lutheran School | School | 231 | Milwaukee | 42 55 52 N | 087 57 06 W |
| Our Lady Chapel | Church | 231 | Brown | 44 35 27 N | 087 46 26 W |
| Our Lady of Charity School | School | 219 | Brown | 44 31 08 N | 088 06 09 W |
| Our Lady of Good Hope Grade School | School | 214 | Milwaukee | 43 08 52 N | 087 57 45 W |
| Our Lady of Loretta Church | Church | 249 | Sauk | 43 21 03 N | 089 54 18 W |
| Our Lady of Lourdes Catholic Cemetery | Cemetery | 363 | Barron | 45 33 16 N | 091 40 58 W |
| Our Lady of Lourdes Church | Church | 362 | Barron | 45 33 14 N | 091 40 58 W |
| Our Lady of Lourdes Community Center | Building | 361 | Barron | 45 33 14 N | 091 41 04 W |
| Our Lady of Lourdes Roman Catholic Church | Church | 182 | Marinette | 45 05 37 N | 087 37 04 W |
| Our Lady of Mount Carmel Catholic Church | Church | 223 | Milwaukee | 43 00 15 N | 087 59 43 W |
| Our Lady of Mount Carmel Church | Church | 189 | Kenosha | 42 35 09 N | 087 49 58 W |
| Our Lady of Mount Carmel School | School | 189 | Kenosha | 42 35 08 N | 087 49 58 W |
| Our Lady of Peace Grade School | School | 399 | Wood | 44 39 57 N | 090 11 37 W |
| Our Lady of Peace Roman Catholic Church | Church | 398 | Wood | 44 39 57 N | 090 11 39 W |
| Our Lady of Perpetual Help Church | Church | 457 | Taylor | 45 13 15 N | 090 19 22 W |
| Our Lady of Sorrows Chapel | Church | 206 | La Crosse | 43 48 19 N | 091 13 07 W |
| Our Lady of Sorrows Roman Catholic Church | Church | 348 | Rusk | 45 27 38 N | 091 05 57 W |
| Our Lady of Sorrows School | School | 211 | Milwaukee | 43 05 30 N | 087 59 33 W |
| Our Lady of Sorrows School | School | 348 | Rusk | 45 27 39 N | 091 05 59 W |
| Our Lady of the Assumption Roman Catholic Church | Church | 243 | Rock | 42 31 48 N | 089 00 12 W |
| Our Lady of the Assumption School | School | 242 | Rock | 42 31 45 N | 089 00 12 W |
| Our Lady of the Fields Chapel | Church | 362 | Sauk | 43 22 25 N | 090 08 00 W |
| Our Lady of the Lake Catholic Church | Church | 251 | Green Lake | 43 50 23 N | 088 57 26 W |
| Our Lady of the Lake Catholic Church | Church | 273 | Juneau | 43 53 32 N | 089 59 09 W |
| Our Lady of the North Church | Church | 451 | Price | 45 41 18 N | 090 23 56 W |
| Our Lady of the Rosary Roman Catholic Church | Church | 189 | Kenosha | 42 35 44 N | 087 50 11 W |
| Our Lady Queen of Heaven Church | Church | 304 | Wood | 44 23 18 N | 089 50 12 W |
| Our Lady Queen of Heaven Grade School | School | 304 | Wood | 44 23 19 N | 089 50 12 W |
| Our Lady Queen of Peace Grade School | School | 310 | Dane | 43 03 34 N | 089 26 45 W |
| Our Lady Queen of Peace Roman Catholic Church | Church | 202 | Milwaukee | 42 59 11 N | 087 56 56 W |
| Our Lady Queen of Peace School | School | 202 | Milwaukee | 42 59 11 N | 087 56 58 W |
| Our Ladys Catholic Church | Church | 226 | Trempealeau | 44 14 57 N | 091 30 02 W |
| Our Lake | Lake | 305 | Burnett | 45 58 28 N | 092 18 23 W |
| Our Lake | Lake | 390 | Langlade | 45 08 51 N | 088 47 03 W |
| Our Redeemer Evangelical Church | Church | 186 | Marinette | 45 05 41 N | 087 38 42 W |
| Our Redeemer Evangelical Lutheran Church | Church | 211 | Milwaukee | 43 03 38 N | 088 01 40 W |
| Our Redeemer Lutheran Church | Church | 233 | Dane | 43 10 38 N | 089 47 39 W |
| Our Redeemer Lutheran Church | Church | 204 | La Crosse | 43 47 28 N | 091 13 26 W |
| Our Redeemer Lutheran Church | Church | 216 | Sheboygan | 43 45 21 N | 087 44 49 W |
| Our Redeemer Lutheran Church | Church | 281 | Walworth | 42 37 37 N | 088 39 29 W |
| Our Redeemer Lutheran School | School | 216 | Milwaukee | 43 03 43 N | 088 01 19 W |
| Our Redeemers Church | Church | 261 | Oconto | 45 00 17 N | 088 18 35 W |
| Our Savior Church | Church | 323 | Pierce | 44 46 26 N | 092 23 41 W |
| Our Savior Church | Church | 331 | Pierce | 44 47 03 N | 092 23 43 W |
| Our Savior Lutheran Church | Church | 198 | Douglas | 46 42 55 N | 092 07 27 W |
| Our Savior Lutheran Church | Church | 244 | Racine | 42 40 15 N | 088 16 37 W |
| Our Savior Lutheran Church | Church | 238 | Rock | 42 30 18 N | 089 02 29 W |
| Our Savior Lutheran Church | Church | 253 | Rock | 42 38 58 N | 089 02 40 W |
| Our Savior Lutheran Church | Church | 503 | Vilas | 45 55 06 N | 089 14 37 W |
| Our Savior Norwegian Lutheran Church | Church | 183 | Marinette | 45 05 30 N | 087 36 55 W |
| Our Saviors Catholic Church | Church | 352 | Marathon | 44 47 34 N | 089 42 37 W |
| Our Saviors Cemetery | Cemetery | 289 | Dunn | 45 02 17 N | 091 55 31 W |
| Our Saviors Cemetery | Cemetery | 311 | Dunn | 45 09 56 N | 091 43 18 W |
| Our Saviors Cemetery | Cemetery | 381 | Marathon | 44 47 07 N | 089 26 17 W |
| Our Saviors Church | Church | 360 | Barron | 45 32 18 N | 091 38 29 W |
| Our Saviors Church | Church | 282 | Shawano | 44 38 52 N | 088 23 02 W |
| Our Saviors English Lutheran Church (historical) | Church | 229 | Winnebago | 44 10 60 N | 088 27 57 W |
| Our Saviors Episcopal Church | Church | 444 | Price | 45 46 34 N | 090 30 14 W |
| Our Saviors Evangelical Lutheran Church | Church | 361 | Marathon | 44 56 29 N | 089 38 36 W |
| Our Saviors Evangelical Lutheran Grade School | School | 361 | Marathon | 44 56 29 N | 089 38 36 W |
| Our Saviors Lutheran Cemetery | Cemetery | 360 | Barron | 45 32 14 N | 091 38 25 W |
| Our Saviors Lutheran Church | Church | 306 | Chippewa | 45 05 54 N | 091 29 06 W |
| Our Saviors Lutheran Church | Church | 271 | Dunn | 44 52 27 N | 091 55 09 W |
| Our Saviors Lutheran Church | Church | 205 | La Crosse | 43 48 23 N | 091 14 54 W |
| Our Saviors Lutheran Church | Church | 210 | Milwaukee | 43 02 22 N | 087 57 08 W |
| Our Saviors Lutheran Church | Church | 265 | Waukesha | 43 07 10 N | 088 29 49 W |