Nonprofits in Wisconsin

Nonprofits in Wisconsin. Browse 46,682 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. Operative Plasterers & Cement Masons Local 599

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

  2. Ophelia Speaks Inc

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

  3. Opportunities Inc of Jefferson County

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

  4. Opportunity 34 Foundation Inc

    EIN 823867354 · Headquarters: VERONA, WI, US · Education · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  5. Opportunity Development Centers Inc

    EIN 391044318 · Headquarters: WISCONSIN RAPIDS, WI, USA · Employment · Latest available filing year: 2024 · Primary form: IRS Form 990

  6. Opportunity League of Washington County Inc

    EIN 391604830 · Headquarters: HARTFORD, WI, US · Recreation & Sports · Latest available filing year: 2013 · Primary form: IRS Form 990-N

  7. Opportunity of North Central Wisconsin Inc

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

  8. Opticians Association of Wisconsin

    EIN 301355947 · Headquarters: WHITEFISH BAY, WI, US · Health Care · Latest available filing year: 2025 · Primary form: IRS Form 990-N

  9. Optima Enrichment Inc

    EIN 200476818 · Headquarters: Brookfield, WI, US · Education · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  10. Optimist Club Foundation of Fond Du Lac

    EIN 391826950 · Headquarters: Fond du Lac, WI, USA · Education · Latest available filing year: 2023 · Primary form: IRS Form 990-PF

  11. 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

  12. Optimist Club of Fond Du Lac

    EIN 396075881 · Headquarters: FOND DU LAC, WI, USA · Community Improvement & Capacity Building · Latest available filing year: 2024 · Primary form: IRS Form 990-EZ

  13. 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

  14. 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

  15. Optimist Club of Howard-suamico

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

  16. 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

  17. Optimist Club of Menomonee Falls Foundation Inc

    EIN 873082223 · Headquarters: MENOMONEE FALLS, WI, USA · Community Improvement & Capacity Building · Latest available filing year: 2023 · Primary form: IRS Form 990

  18. 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

  19. 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

  20. Optimist Club of Middleton Inc

    EIN 396075878 · Headquarters: MIDDLETON, WI, USA · Youth Development · Latest available filing year: 2012 · Primary form: IRS Form 990-EZ

  21. Optimist Club of Mount Horeb Wisconsin Inc

    EIN 391834943 · Headquarters: Mount Horeb, WI, US · Youth Development · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  22. 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

  23. Optimist International

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

  24. Optimist International

    EIN 237032192 · Headquarters: Chippewa Falls, WI, US · Youth Development · Latest available filing year: 2010 · Primary form: IRS Form 990-N

  25. Optimist International

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

  26. Optimist International

    EIN 237043016 · Headquarters: Portage, WI, US · Youth Development · Latest available filing year: 2008 · Primary form: IRS Form 990-N

  27. Optimist International

    EIN 237047752 · Headquarters: Fond du Lac, WI, US · Youth Development · Latest available filing year: 2014 · Primary form: IRS Form 990-N

  28. Optimist International

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

  29. Optimist International

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

  30. Optimist International

    EIN 237327064 · Headquarters: Sturgeon Bay, WI, US · Youth Development · Latest available filing year: 2012 · Primary form: IRS Form 990-N

  31. Optimist International

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

  32. Optimist International

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

  33. Optimist International

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

  34. Optimist International

    EIN 391097382 · Headquarters: Sun Prairie, WI, US · Youth Development · Latest available filing year: 2016 · Primary form: IRS Form 990-N

  35. Optimist International

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

  36. Optimist International

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

  37. Optimist International

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

  38. Optimist International

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

  39. Optimist International

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

  40. Optimist International

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

  41. Optimist International

    EIN 391654715 · Headquarters: MILTON, WI, US · Philanthropy, Voluntarism & Grantmaking Foundations · Latest available filing year: 2016 · Primary form: IRS Form 990-N

  42. Optimist International

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

  43. Optimist International

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

  44. Optimist International

    EIN 391667029 · Headquarters: MONONA, WI, US · Youth Development · Latest available filing year: 2010 · Primary form: IRS Form 990-N

  45. Optimist International

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

  46. Optimist International

    EIN 391678435 · Headquarters: PLYMOUTH, WI, US · Youth Development · Latest available filing year: 2010 · Primary form: IRS Form 990-N

  47. Optimist International

    EIN 391680677 · Headquarters: Delavan, WI, US · Youth Development · Latest available filing year: 2012 · Primary form: IRS Form 990-N

  48. Optimist International

    EIN 391682015 · Headquarters: Tomahawk, WI, US · Youth Development · Latest available filing year: 2011 · Primary form: IRS Form 990-N

  49. Optimist International

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

  50. Optimist International

    EIN 391685560 · Headquarters: OSSEO, WI, US · Youth Development · Latest available filing year: 2009 · Primary form: IRS Form 990-N

  51. Optimist International

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

  52. Optimist International

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

  53. Optimist International

    EIN 391716468 · Headquarters: Durand, WI, US · Youth Development · Latest available filing year: 2016 · Primary form: IRS Form 990-N

  54. Optimist International

    EIN 391716471 · Headquarters: Whitewater, WI, US · Youth Development · Latest available filing year: 2008 · Primary form: IRS Form 990-N

  55. Optimist International

    EIN 391719383 · Headquarters: JANESVILLE, WI, US · Mutual & Membership Benefit · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  56. Optimist International

    EIN 391723876 · Headquarters: Oshkosh, WI, US · Youth Development · Latest available filing year: 2007 · Primary form: IRS Form 990-N

  57. Optimist International

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

  58. Optimist International

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

  59. Optimist International

    EIN 391805636 · Headquarters: OOSTBURG, WI, US · Youth Development · Latest available filing year: 2013 · Primary form: IRS Form 990-N

  60. Optimist International

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

  61. Optimist International

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

  62. Optimist International

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

  63. Optimist International

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

  64. Optimist International

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

  65. Optimist International

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

  66. Optimist International

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

  67. Optimist International

    EIN 396062852 · Headquarters: Waukesha, WI, US · Youth Development · Latest available filing year: 2011 · Primary form: IRS Form 990-N

  68. Optimist International

    EIN 396075873 · Headquarters: Neenah, WI, US · Youth Development · Latest available filing year: 2014 · Primary form: IRS Form 990-N

  69. Optimist International

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

  70. Optimist International

    EIN 396077554 · Headquarters: Madison, WI, US · Youth Development · Latest available filing year: 2011 · Primary form: IRS Form 990-N

  71. Optimist International

    EIN 396077969 · Headquarters: MILWAUKEE, WI, US · Youth Development · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  72. Optimist International

    EIN 396078128 · Headquarters: Stevens point, WI, US · Youth Development · Latest available filing year: 2008 · Primary form: IRS Form 990-N

  73. Optimist International

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

  74. Optimist International

    EIN 396081140 · Headquarters: LA CROSSE, WI, US · Youth Development · Latest available filing year: 2008 · Primary form: IRS Form 990-N

  75. Optimist International

    EIN 396088391 · Headquarters: Sheboygan, WI, US · Youth Development · Latest available filing year: 2012 · Primary form: IRS Form 990-N

  76. Optimist International

    EIN 396093914 · Headquarters: DePere, WI, US · Youth Development · Latest available filing year: 2010 · Primary form: IRS Form 990-N

  77. Optimist International

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

  78. Optimist International

    EIN 396099819 · Headquarters: De Pere, WI, US · Youth Development · Latest available filing year: 2017 · Primary form: IRS Form 990-N

  79. Optimist International

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

  80. Optimist International

    EIN 396121820 · Headquarters: Mc Farland, WI, US · Youth Development · Latest available filing year: 2016 · Primary form: IRS Form 990-N

  81. Optimist International

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

  82. Optimist International

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

  83. Optimist International

    EIN 396123831 · Headquarters: Baraboo, WI, US · Youth Development · Latest available filing year: 2009 · Primary form: IRS Form 990-N

  84. Optimist International

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

  85. Optimist International

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

  86. Optimist International

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

  87. Optimist International

    EIN 396125994 · Headquarters: Algoma, WI, US · Youth Development · Latest available filing year: 2014 · Primary form: IRS Form 990-N

  88. Optimist International

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

  89. Optimist International

    EIN 398059544 · Headquarters: Manitowoc, WI, US · Youth Development · Latest available filing year: 2013 · Primary form: IRS Form 990-N

  90. Optimist International

    EIN 411614989 · Headquarters: La Crosse, WI, US · Youth Development · Latest available filing year: 2008 · Primary form: IRS Form 990-N

  91. Optimist International

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

  92. Optimist International

    EIN 464458249 · Headquarters: Fremont, WI, US · Youth Development · Latest available filing year: 2015 · Primary form: IRS Form 990-N

  93. Optimist International

    EIN 472046768 · Headquarters: Monticello, WI, US · Youth Development · Latest available filing year: 2015 · Primary form: IRS Form 990-N

  94. Optimist International

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

  95. Optimist International

    EIN 510192306 · Headquarters: Thiensville, WI, US · Youth Development · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  96. Optimist International

    EIN 510200101 · Headquarters: Pulaski, WI, US · Youth Development · Latest available filing year: 2009 · Primary form: IRS Form 990-N

  97. Optimist International

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

  98. Optimist International

    EIN 510219133 · Headquarters: Menomonie, WI, US · Youth Development · Latest available filing year: 2024 · Primary form: IRS Form 990-N

  99. Optimist International

    EIN 631034465 · Headquarters: Kenosha, WI, US · Youth Development · Latest available filing year: 2008 · Primary form: IRS Form 990-N

  100. Optimist International

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

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