| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
|---|
| Oak Center | city | Wisconsin | United States | 43.66083 | -88.6 | 898 | 2030 |
| Oak Creek | city | Wisconsin | United States | 42.88583 | -87.86306 | 721 | 48697 |
| Oak Grove | city | Wisconsin | United States | 43.38611 | -88.74556 | 882 | 2943 |
| Oak Grove historical | city | Wisconsin | United States | 44.6725 | -91.605 | 974 | 1601 |
| Oak Hall | city | Wisconsin | United States | 42.95056 | -89.43694 | 1026 | 8333 |
| Oak Hill | city | Wisconsin | United States | 42.93583 | -88.58667 | 892 | 3266 |
| Oak Knoll | city | Wisconsin | United States | 42.94278 | -89.21861 | 898 | 14958 |
| Oak Knoll | city | Wisconsin | United States | 42.86861 | -88.33778 | 797 | 13009 |
| Oak Orchard | city | Wisconsin | United States | 44.78139 | -87.92583 | 577 | 888 |
| Oakdale | city | Wisconsin | United States | 43.95972 | -90.38167 | 944 | 1276 |
| Oakfield | city | Wisconsin | United States | 43.68611 | -88.54639 | 948 | 2000 |
| Oakland | city | Wisconsin | United States | 45.9375 | -92.36861 | 948 | 1012 |
| Oakland | city | Wisconsin | United States | 42.97667 | -88.95556 | 856 | 3069 |
| Oakland Heights | city | Wisconsin | United States | 43.06611 | -89.41194 | 853 | 116741 |
| Oakley | city | Wisconsin | United States | 42.52694 | -89.46778 | 948 | 1592 |
| Oakridge | city | Wisconsin | United States | 44.58833 | -92.39528 | 1030 | 1238 |
| Oakwood | city | Wisconsin | United States | 44.04639 | -88.60278 | 748 | 23719 |
| Oakwood | city | Wisconsin | United States | 42.85806 | -87.92444 | 698 | 18497 |
| Oconomowoc | city | Wisconsin | United States | 43.11167 | -88.49917 | 875 | 19928 |
| Oconomowoc Lake | city | Wisconsin | United States | 43.10444 | -88.45917 | 859 | 19928 |
| Oconto | city | Wisconsin | United States | 44.88722 | -87.86444 | 590 | 2054 |
| Oconto Falls | city | Wisconsin | United States | 44.87389 | -88.14278 | 738 | 2724 |
| Odanah | city | Wisconsin | United States | 46.60833 | -90.69667 | 613 | 218 |
| Ogdensburg | city | Wisconsin | United States | 44.45194 | -89.03167 | 849 | 2112 |
| Ogema | city | Wisconsin | United States | 45.44361 | -90.29806 | 1574 | 419 |
| Oil City | city | Wisconsin | United States | 43.75056 | -90.58667 | 1026 | 1069 |
| Ojibwa | city | Wisconsin | United States | 45.79806 | -91.11667 | 1315 | 338 |
| Okauchee | city | Wisconsin | United States | 43.11361 | -88.43583 | 898 | 15595 |
| Okauchee Lake | city | Wisconsin | United States | 43.12333 | -88.44056 | 869 | 15595 |
| Okee | city | Wisconsin | United States | 43.35778 | -89.58 | 797 | 2861 |
| Old Albertville | city | Wisconsin | United States | 44.93667 | -91.6 | 997 | 1540 |
| Old Ashippun | city | Wisconsin | United States | 43.22472 | -88.51972 | 1000 | 3735 |
| Old Deerfield | city | Wisconsin | United States | 43.08306 | -89.07556 | 892 | 3262 |
| Old Fort | city | Wisconsin | United States | 46.75472 | -90.78222 | 643 | 239 |
| Old Lebanon | city | Wisconsin | United States | 43.22611 | -88.63028 | 948 | 3900 |
| Old Tyrone historical | city | Wisconsin | United States | 44.71389 | -91.8425 | 774 | 1108 |
| Oliver | city | Wisconsin | United States | 46.6575 | -92.195 | 695 | 5751 |
| Olivet | city | Wisconsin | United States | 44.78639 | -92.25694 | 1207 | 1429 |
| Omro | city | Wisconsin | United States | 44.03944 | -88.74417 | 793 | 2913 |
| Onalaska | city | Wisconsin | United States | 43.88444 | -91.235 | 679 | 24044 |
| Oneida | city | Wisconsin | United States | 44.49861 | -88.18278 | 662 | 5012 |
| Ono | city | Wisconsin | United States | 44.65556 | -92.25611 | 1148 | 924 |
| Ontario | city | Wisconsin | United States | 43.72583 | -90.59139 | 882 | 1081 |
| Oostburg | city | Wisconsin | United States | 43.62278 | -87.79444 | 698 | 4721 |
| Orange Mill | city | Wisconsin | United States | 43.90167 | -90.23222 | 905 | 1245 |
| Orchard Grove | city | Wisconsin | United States | 43.49833 | -88.14083 | 951 | 16138 |
| Oregon | city | Wisconsin | United States | 42.92611 | -89.38444 | 984 | 10233 |
| Orfordville | city | Wisconsin | United States | 42.6275 | -89.25306 | 898 | 1877 |
| Orihula | city | Wisconsin | United States | 44.20917 | -88.83278 | 748 | 2544 |
| Orion | city | Wisconsin | United States | 43.20306 | -90.42778 | 659 | 1017 |
| Ormsby | city | Wisconsin | United States | 45.25611 | -89.2525 | 1499 | 522 |
| Orva | city | Wisconsin | United States | 46.45194 | -90.23139 | 1450 | 4869 |
| Osceola | city | Wisconsin | United States | 45.32056 | -92.70472 | 866 | 2601 |
| Oshkosh | city | Wisconsin | United States | 44.02472 | -88.5425 | 757 | 54295 |
| Osman | city | Wisconsin | United States | 43.96861 | -87.82083 | 774 | 2400 |
| Osseo | city | Wisconsin | United States | 44.57222 | -91.22722 | 984 | 1322 |
| Ostrander | city | Wisconsin | United States | 44.39278 | -88.83778 | 797 | 2347 |
| Otis | city | Wisconsin | United States | 45.26889 | -89.69333 | 1348 | 1470 |
| Otsego | city | Wisconsin | United States | 43.40222 | -89.16611 | 997 | 1482 |
| Ottawa | city | Wisconsin | United States | 42.97611 | -88.44972 | 1030 | 8387 |
| Ottman Corners | city | Wisconsin | United States | 44.70333 | -92.51694 | 1033 | 1967 |
| Oulu | city | Wisconsin | United States | 46.63306 | -91.53167 | 1017 | 328 |
| Ourtown | city | Wisconsin | United States | 43.69722 | -87.82111 | 692 | 6494 |
| Owen | city | Wisconsin | United States | 44.94861 | -90.56417 | 1230 | 1442 |
| Oxbo | city | Wisconsin | United States | 45.86278 | -90.70417 | 1381 | 306 |
| Oxford | city | Wisconsin | United States | 43.78139 | -89.5725 | 885 | 1733 |
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