| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| O Kleras | city | Wisconsin | United States | 44.81 | -91.50 | 830 | |
| Oak Center | city | Wisconsin | United States | 43.66 | -88.60 | 898 | |
| Oak Creek | city | Wisconsin | United States | 42.89 | -87.86 | 830 | |
| Oak Grove | city | Wisconsin | United States | 43.39 | -88.75 | 882 | |
| Oak Grove (historical) | city | Wisconsin | United States | 44.67 | -91.61 | 974 | |
| Oak Hall | city | Wisconsin | United States | 42.95 | -89.44 | 1026 | |
| Oak Hill | city | Wisconsin | United States | 42.94 | -88.59 | 892 | |
| Oak Hill Mobile Home Park | city | Wisconsin | United States | 44.59 | -92.46 | 830 | |
| Oak Knoll | city | Wisconsin | United States | 42.87 | -88.34 | 830 | |
| Oak Knoll | city | Wisconsin | United States | 42.94 | -89.22 | 898 | |
| Oak Orchard | city | Wisconsin | United States | 44.78 | -87.93 | 830 | |
| Oak Park Terrace | city | Wisconsin | United States | 43.13 | -89.35 | 849 | |
| Oak Ridge Estates | city | Wisconsin | United States | 43.17 | -90.08 | 830 | |
| Oak Ridge Village Mobile Home Park | city | Wisconsin | United States | 44.79 | -91.54 | 830 | |
| Oakdale | city | Wisconsin | United States | 43.96 | -90.38 | 944 | |
| Oakdale Estates | city | Wisconsin | United States | 42.67 | -87.95 | 830 | |
| Oakfield | city | Wisconsin | United States | 43.69 | -88.55 | 948 | |
| Oakland | city | Wisconsin | United States | 45.94 | -92.37 | 948 | |
| Oakland | city | Wisconsin | United States | 42.98 | -88.96 | 856 | |
| Oakland Heights | city | Wisconsin | United States | 43.07 | -89.41 | 853 | |
| Oakley | city | Wisconsin | United States | 42.53 | -89.47 | 948 | |
| Oakridge | city | Wisconsin | United States | 44.59 | -92.40 | 1030 | |
| Oakwood | city | Wisconsin | United States | 44.05 | -88.60 | 830 | |
| Oakwood | city | Wisconsin | United States | 42.86 | -87.92 | 830 | |
| Oakwood Mobile Home Community | city | Wisconsin | United States | 42.54 | -87.83 | 830 | |
| Oconomowoc | city | Wisconsin | United States | 43.11 | -88.50 | 875 | |
| Oconomowoc Lake | city | Wisconsin | United States | 43.10 | -88.46 | 859 | |
| Oconto | city | Wisconsin | United States | 44.89 | -87.86 | 830 | |
| Oconto Falls | city | Wisconsin | United States | 44.87 | -88.14 | 830 | |
| Odanah | city | Wisconsin | United States | 46.61 | -90.70 | 830 | |
| Ogdensburg | city | Wisconsin | United States | 44.45 | -89.03 | 849 | |
| Ogema | city | Wisconsin | United States | 45.44 | -90.30 | 1669 | |
| Oil City | city | Wisconsin | United States | 43.75 | -90.59 | 1026 | |
| Ojibwa | city | Wisconsin | United States | 45.80 | -91.12 | 1669 | |
| Okauchee | city | Wisconsin | United States | 43.11 | -88.44 | 898 | |
| Okauchee Lake | city | Wisconsin | United States | 43.12 | -88.44 | 869 | |
| Okee | city | Wisconsin | United States | 43.36 | -89.58 | 830 | |
| Oklēra | city | Wisconsin | United States | 44.81 | -91.50 | 830 | |
| Old Albertville | city | Wisconsin | United States | 44.94 | -91.60 | 997 | |
| Old Ashippun | city | Wisconsin | United States | 43.22 | -88.52 | 1000 | |
| Old Deerfield | city | Wisconsin | United States | 43.08 | -89.08 | 892 | |
| Old Fort | city | Wisconsin | United States | 46.75 | -90.78 | 830 | |
| Old Lebanon | city | Wisconsin | United States | 43.23 | -88.63 | 948 | |
| Old Tyrone (historical) | city | Wisconsin | United States | 44.71 | -91.84 | 830 | |
| Oliver | city | Wisconsin | United States | 46.66 | -92.20 | 830 | |
| Olivet | city | Wisconsin | United States | 44.79 | -92.26 | 1207 | |
| Olympic Village | city | Wisconsin | United States | 44.34 | -87.82 | 856 | |
| Omro | city | Wisconsin | United States | 44.04 | -88.74 | 830 | |
| Onalaska | city | Wisconsin | United States | 43.88 | -91.24 | 830 | |
| Oneida | city | Wisconsin | United States | 44.50 | -88.18 | 830 | |
| Ono | city | Wisconsin | United States | 44.66 | -92.26 | 1148 | |
| Ontario | city | Wisconsin | United States | 43.73 | -90.59 | 882 | |
| Oostburg | city | Wisconsin | United States | 43.62 | -87.79 | 830 | |
| Orange Mill | city | Wisconsin | United States | 43.90 | -90.23 | 905 | |
| Orchard Grove | city | Wisconsin | United States | 43.50 | -88.14 | 951 | |
| Oregon | city | Wisconsin | United States | 42.93 | -89.38 | 984 | |
| Oregono | city | Wisconsin | United States | 42.93 | -89.38 | 984 | |
| Orfordville | city | Wisconsin | United States | 42.63 | -89.25 | 898 | |
| Orihula | city | Wisconsin | United States | 44.21 | -88.83 | 830 | |
| Orion | city | Wisconsin | United States | 43.20 | -90.43 | 830 | |
| Ormsby | city | Wisconsin | United States | 45.26 | -89.25 | 1669 | |
| Orva | city | Wisconsin | United States | 46.45 | -90.23 | 1669 | |
| Osceola | city | Wisconsin | United States | 45.32 | -92.70 | 866 | |
| Oshkosh | city | Wisconsin | United States | 44.02 | -88.54 | 830 | |
| Osman | city | Wisconsin | United States | 43.97 | -87.82 | 830 | |
| Osseo | city | Wisconsin | United States | 44.57 | -91.23 | 984 | |
| Ostrander | city | Wisconsin | United States | 44.39 | -88.84 | 830 | |
| Otis | city | Wisconsin | United States | 45.27 | -89.69 | 1669 | |
| Otsego | city | Wisconsin | United States | 43.40 | -89.17 | 997 | |
| Ottawa | city | Wisconsin | United States | 42.98 | -88.45 | 1030 | |
| Ottman Corners | city | Wisconsin | United States | 44.70 | -92.52 | 1033 | |
| Oulu | city | Wisconsin | United States | 46.63 | -91.53 | 1017 | |
| Ourtown | city | Wisconsin | United States | 43.70 | -87.82 | 830 | |
| Owen | city | Wisconsin | United States | 44.95 | -90.56 | 1230 | |
| Oxbo | city | Wisconsin | United States | 45.86 | -90.70 | 1669 | |
| Oxford | city | Wisconsin | United States | 43.78 | -89.57 | 885 |