Unknown & Unclassified nonprofits in Wisconsin

Unknown & Unclassified nonprofits in Wisconsin. Browse 13,737 public nonprofit profiles. Review organization identities, available filing years, and their complete CharitySense profiles.

Location refers to headquarters recorded in public sources, not an organization’s service area. Classification describes its reported category and does not assess its effectiveness.

Nonprofit profiles

  1. Odyssey Con Society

    EIN 471698598 · Headquarters: Madison, WI, US · Unknown & Unclassified · Latest available filing year: 2019 · Primary form: IRS Form 990-N

  2. Off the Table Farm Sanctuary Inc

    EIN 862663338 · Headquarters: Westfield, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  3. Office and Professional Employees International Union

    EIN 390791784 · Headquarters: Madison, WI, USA · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990

  4. Oh Schlit Research Labs Inc

    EIN 393358247 · Headquarters: Grafton, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  5. Ohelaku Among the Corn Stalks

    EIN 384026057 · Headquarters: DE PERE, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  6. Ohioans for Fair Maps

    EIN 933425918 · Headquarters: Hudson, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  7. Okauchee Fire Department

    EIN 237454962 · Headquarters: OKAUCHEE, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  8. Oktoberfest Singers

    EIN 391739813 · Headquarters: La Crosse, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  9. Old Boys Scholarship Foundation

    EIN 396036633 · Headquarters: DELAFIELD, WI, USA · Unknown & Unclassified · Latest available filing year: 2020 · Primary form: IRS Form 990-PF

  10. Old Middleton Road Apartments Inc

    EIN 201427325 · Headquarters: MADISON, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  11. Old World Wisconsin Foundation Inc

    EIN 391484170 · Headquarters: ELKHORN, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  12. Olde Norwood Neighborhood Association

    EIN 261820658 · Headquarters: green bay, WI, US · Unknown & Unclassified · Latest available filing year: 2014 · Primary form: IRS Form 990-N

  13. Olga V Alexandria Fdn

    EIN 942936907 · Headquarters: MILWAUKEE, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-PF

  14. Oliver T Donovan Tw

    EIN 396045096 · Headquarters: GREEN BAY, WI, USA · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-PF

  15. Olivia C Eaton Trust R55945001

    EIN 900330188 · Headquarters: MILWAUKEE, WI, USA · Unknown & Unclassified · Latest available filing year: 2011 · Primary form: IRS Form 990-PF

  16. Omega Enterprises Veba Associated Trust Co Na

    EIN 396514138 · Headquarters: GREEN BAY, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  17. Omega School Inc

    EIN 391166888 · Headquarters: MADISON, WI, USA · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990

  18. Omicron Kappa Upsilon Honorary Dental Society

    EIN 237134586 · Headquarters: Milwaukee, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  19. Omro Education Association

    EIN 391706995 · Headquarters: MADISON, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  20. Omro High School Alumni Association Omro High School

    EIN 396099505 · Headquarters: OMRO, WI, US · Unknown & Unclassified · Latest available filing year: 2019 · Primary form: IRS Form 990-N

  21. Omro Paraprofessional Food Service Association

    EIN 391752944 · Headquarters: MADISON, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  22. Omro Veterans Memorial Inc

    EIN 300655228 · Headquarters: Omro, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  23. Onalaska Area Business Assn

    EIN 391606101 · Headquarters: Onalaska, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  24. Onalaska Area Historical Society Inc

    EIN 391552879 · Headquarters: Onalaska, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  25. Onalaska Education Association

    EIN 237272295 · Headquarters: MADISON, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  26. Onalaska Emergency Food Basket

    EIN 391484972 · Headquarters: Onalaska, WI, USA · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990

  27. Onalaska Volleyball Booster Club

    EIN 273336808 · Headquarters: Onalaska, WI, US · Unknown & Unclassified · Latest available filing year: 2013 · Primary form: IRS Form 990-N

  28. Onalaskaholmen Tornado Youth Hockey

    EIN 391500008 · Headquarters: ONALASKA, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  29. One Drum Solutions Inc

    EIN 391866016 · Headquarters: Ashland, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  30. One Love Harmonizing Mind Body Spirit

    EIN 812457277 · Headquarters: APPLETON, WI, US · Unknown & Unclassified · Latest available filing year: 2022 · Primary form: IRS Form 990-N

  31. Oneida County Fair Committee Inc

    EIN 852902805 · Headquarters: RHINELANDER, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-EZ

  32. Oneida County Humane Society

    EIN 391312508 · Headquarters: Rhinelander, WI, USA · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990

  33. Oneida Golf and Country Club Inc

    EIN 390518065 · Headquarters: GREEN BAY, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  34. Oneota Housing Inc

    EIN 237183641 · Headquarters: LA CROSSE, WI, USA · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990

  35. Ong First Friends Church Trust

    EIN 930548829 · Headquarters: MILWAUKEE, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-PF

  36. Oostburg Education Association

    EIN 753267758 · Headquarters: MADISON, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  37. OPEIU Local 9

    EIN 390513924 · Headquarters: Milwaukee, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990

  38. Opening More Doors Together LLC

    EIN 931734836 · Headquarters: Lake Mills, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  39. Operating Engineers Local 139 Health Benefit Fund

    EIN 237166771 · Headquarters: PEWAUKEE, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  40. Operation Chess

    EIN 264557407 · Headquarters: Milwaukee, WI, US · Unknown & Unclassified · Latest available filing year: 2014 · Primary form: IRS Form 990-N

  41. Operation Help Inc

    EIN 391711703 · Headquarters: HUDSON, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  42. Operation K9 Hero Corporation

    EIN 861807160 · Headquarters: Neenah, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  43. Operation Sparrow Corp

    EIN 823885921 · Headquarters: Nekoosa, WI, US · Unknown & Unclassified · Latest available filing year: 2018 · Primary form: IRS Form 990-N

  44. Operative Plasterers & Cement Masons Local 599

    EIN 391960564 · Headquarters: MILWAUKEE, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  45. Ophelia Speaks Inc

    EIN 854015802 · Headquarters: Milwaukee, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  46. Opportunities Inc of Jefferson County

    EIN 391078133 · Headquarters: FORT ATKINSON, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  47. Opportunity of North Central Wisconsin Inc

    EIN 390975675 · Headquarters: WAUSAU, WI, USA · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990

  48. Optimist Club of Allouez Green Bay Wisc Dba Optimist International

    EIN 510205996 · Headquarters: GREEN BAY, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-EZ

  49. Optimist Club of Green Bay Foundation Inc

    EIN 391775441 · Headquarters: Green Bay, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990

  50. Optimist Club of Green Bay Inc

    EIN 396079687 · Headquarters: GREEN BAY, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-EZ

  51. Optimist Club of Howard-suamico

    EIN 237297962 · Headquarters: SUAMICO, WI, US · Unknown & Unclassified · Latest available filing year: 2022 · Primary form: IRS Form 990-N

  52. Optimist Club of Madison Foundation Inc

    EIN 391395176 · Headquarters: OREGON, WI, USA · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-EZ

  53. Optimist Club of Menomonee Falls Inc

    EIN 237297960 · Headquarters: MENOMONEE FALLS, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-EZ

  54. Optimist Club of Merrill Wisconsin Inc

    EIN 396126962 · Headquarters: MERRILL, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-EZ

  55. Optimist Club of Waunakee Wisconsin Inc

    EIN 930826012 · Headquarters: WAUNAKEE, WI, USA · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-EZ

  56. Optimist International

    EIN 237003917 · Headquarters: Antigo, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  57. Optimist International

    EIN 237032820 · Headquarters: Oregon, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  58. Optimist International

    EIN 237098026 · Headquarters: Janesville, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  59. Optimist International

    EIN 237118773 · Headquarters: FOND DU LAC, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  60. Optimist International

    EIN 320014563 · Headquarters: Brodhead, WI, US · Unknown & Unclassified · Latest available filing year: 2022 · Primary form: IRS Form 990-N

  61. Optimist International

    EIN 371578834 · Headquarters: Portage, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  62. Optimist International

    EIN 390518715 · Headquarters: Racine, WI, USA · Unknown & Unclassified · Latest available filing year: 2022 · Primary form: IRS Form 990-EZ

  63. Optimist International

    EIN 391350860 · Headquarters: MCFARLAND, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  64. Optimist International

    EIN 391366404 · Headquarters: Fort Atkinson, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  65. Optimist International

    EIN 391366405 · Headquarters: KIEL, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  66. Optimist International

    EIN 391514922 · Headquarters: EAU CLAIRE, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  67. Optimist International

    EIN 391518207 · Headquarters: Green Bay, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  68. Optimist International

    EIN 391612213 · Headquarters: Prentice, WI, US · Unknown & Unclassified · Latest available filing year: 2020 · Primary form: IRS Form 990-N

  69. Optimist International

    EIN 391656158 · Headquarters: NEW HOLSTEIN, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  70. Optimist International

    EIN 391667026 · Headquarters: West Bend, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  71. Optimist International

    EIN 391673025 · Headquarters: Manitowoc, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  72. Optimist International

    EIN 391682016 · Headquarters: Neillsville, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  73. Optimist International

    EIN 391699694 · Headquarters: Greenleaf, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  74. Optimist International

    EIN 391709939 · Headquarters: Cross Plains, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  75. Optimist International

    EIN 391739351 · Headquarters: MADISON, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  76. Optimist International

    EIN 391765424 · Headquarters: Sheboygan, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  77. Optimist International

    EIN 391813998 · Headquarters: Sherwood, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  78. Optimist International

    EIN 391814012 · Headquarters: TWO RIVERS, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  79. Optimist International

    EIN 391821104 · Headquarters: North Prairie, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  80. Optimist International

    EIN 396057697 · Headquarters: Sheboygan, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  81. Optimist International

    EIN 396059241 · Headquarters: NEENAH, WI, US · Unknown & Unclassified · Latest available filing year: 2019 · Primary form: IRS Form 990-N

  82. Optimist International

    EIN 396060211 · Headquarters: MADISON, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  83. Optimist International

    EIN 396060648 · Headquarters: Appleton, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  84. Optimist International

    EIN 396077396 · Headquarters: SUPERIOR, WI, US · Unknown & Unclassified · Latest available filing year: 2020 · Primary form: IRS Form 990-N

  85. Optimist International

    EIN 396079953 · Headquarters: Sauk City, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  86. Optimist International

    EIN 396096614 · Headquarters: MADISON, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  87. Optimist International

    EIN 396121248 · Headquarters: Madison, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  88. Optimist International

    EIN 396123338 · Headquarters: PLATTEVILLE, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  89. Optimist International

    EIN 396123365 · Headquarters: Green Bay, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  90. Optimist International

    EIN 396123861 · Headquarters: Verona, WI, US · Unknown & Unclassified · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  91. Optimist International

    EIN 396124349 · Headquarters: Lodi, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  92. Optimist International

    EIN 396124876 · Headquarters: BRILLION, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  93. Optimist International

    EIN 396126289 · Headquarters: BELOIT, WI, US · Unknown & Unclassified · Latest available filing year: 2020 · Primary form: IRS Form 990-N

  94. Optimist International

    EIN 431477121 · Headquarters: JEFFERSON, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  95. Optimist International

    EIN 510192303 · Headquarters: Green Bay, WI, US · Unknown & Unclassified · Latest available filing year: 2022 · Primary form: IRS Form 990-N

  96. Optimist International

    EIN 510200108 · Headquarters: Shawano, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  97. Optimist International

    EIN 800343002 · Headquarters: Baraboo, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

  98. Optimist International

    EIN 823485686 · Headquarters: Sussex, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  99. Optimist International

    EIN 832167964 · Headquarters: Chippewa Falls, WI, US · Unknown & Unclassified · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  100. Optimist International

    EIN 834098963 · Headquarters: Hartland, WI, US · Unknown & Unclassified · Latest available filing year: 2023 · Primary form: IRS Form 990-N

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