| New Horizons IncNew Hampton | Form 990-EZ | $143,070FY2025 |
| Woodbury County Conservation FoundationSioux City | Form 990-EZ | $136,765FY2025 |
| Shelby County Trails Board IncHarlan | Form 990-EZ | $132,429FY2023 |
| 1000 Friends of IowaDes Moines | Form 990-EZ | $131,527FY2025 |
| Benton County Conservation FoundationVinton | Form 990-EZ | $123,870FY2024 |
| Jefferson County Farmers and Neighbors IncFairfield | Form 990-EZ | $118,608FY2024 |
| Friends of Webster County ConservationFort Dodge | Form 990 | $116,355FY2025 |
| Conservation Foundation of Jefferson County IowaFairfield | Form 990-EZ | $112,853FY2025 |
| Izaak Wlaton League of America IncDes Moines | Form 990 | $107,379FY2025 |
| Friends of Jackson County ConservationMaquoketa | Form 990-EZ | $102,399FY2026 |
| Izaak Walton League of America IncDavenport | Form 990 | $98,300FY2025 |
| Five Island Trail CorporationEmmetsburg | Form 990-EZ | $91,637FY2024 |
| Driftless Water DefendersIowa City | Form 990-EZ | $85,784FY2025 |
| Friends of Calkins Nature AreaIowa Falls | Form 990-EZ | $81,164FY2025 |
| Friends of Clay County Conservation Foundation IncSpencer | Form 990-EZ | $81,049FY2025 |
| Dallas County Conservation FoundationPerry | Form 990-EZ | $80,831FY2024 |
| Friends of Lake PanoramaPanora | Form 990-EZ | $79,253FY2025 |
| Forest City Enhancement CommitteeForest City | Form 990-EZ | $76,290FY2025 |
| Iowa Recycling Association IncorporatedDavenport | Form 990-EZ | $71,187FY2025 |
| Iowa Association for Energy EfficiencyPleasant Hill | Form 990-EZ | $69,724FY2025 |
| Leopold Landscape AllianceBurlington | Form 990 | $67,045FY2025 |
| Friends of Lake Darling State ParkBrighton | Form 990 | $59,460FY2025 |
| Friends of the Yellow River State Forest IncHarpers Ferry | Form 990-EZ | $57,211FY2025 |
| Linn County Community Action FundCedar Rapids | Form 990-EZ | $53,043FY2025 |
| Ida County Conservation FoundationIda Grove | Form 990-EZ | $52,376FY2025 |
| Izaak Walton League Ottumwa ChapterOttumwa | Form 990 | $51,186FY2024 |
| Carroll County Conservation FoundationCarroll | Form 990-EZ | $46,372FY2025 |
| Worth County Conservation FoundationNorthwood | Form 990 | $46,228FY2024 |
| Limestone Bluffs Resource Conservation and Development IncMechanicsville | Form 990-N | No figure |
| Northern Iowa River Greenbelt AssociationBelmond | Form 990-EZ | $37,437FY2025 |
| Allamakee County Conservation FoundationLansing | Form 990-EZ | $32,345FY2025 |
| Des Moines Founders Garden ClubWest Des Moines | Form 990-N | No figure |
| The Federated Garden Clubs of Iowa IncKnoxville | Form 990-N | No figure |
| Waters Edge Nature Center FoundationAlgona | Form 990-N | No figure |
| Association for the Preservation of Clear LakeClear Lake | Form 990-N | No figure |
| Friends of Carlisle Parks IncCarlisle | Form 990-N | No figure |
| Grindstone Lake Foundation IncCedar Rapids | Form 990-N | No figure |
| Iowa Conservation Educationcoalition IncAckley | Form 990-N | No figure |
| Iowa Native Plant SocietyUrbandale | Form 990-N | No figure |
| Back to Ground Natural Burial CemeteryIowa City | Form 990-N | No figure |
| Technical Service Providers Network IncAmes | Form 990-N | No figure |
| Growing Green Communities IncDes Moines | Form 990-N | No figure |
| The Federated Garden Clubs of Iowa IncPella | Form 990-N | No figure |
| The Carter Lake Preservation Society IncCarter Lake | Form 990-N | No figure |
| Nishnabotna Conservation FoundationHarlan | Form 990-N | No figure |
| Wapello Heritage Foundation IncBloomfield | Form 990-N | No figure |
| Cascade Community Enhancement CorpCascade | Form 990-N | No figure |
| Rock Creek Lake AllianceGrinnell | Form 990-N | No figure |
| Howard County Environmental & Conservation Education FoundationCresco | Form 990-N | No figure |
| West Tarkio Watershed and Lake Alliance IncShenandoah | Form 990-N | No figure |