| DUCK KEY COMMUNITY BENEFIT INC.Duck Key, FL · Active | Duck Key, FL | Nonprofit | Feb 9, 2015 | Active |
| SOLID AS A ROCK INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 21, 2015 | Inactive |
| VIETNAM VETERANS OF AMERICA CHAPTER #1111, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Jun 29, 2015 | Inactive |
| COOLE OBSERVATIONS FOUNDATION INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Sep 24, 2015 | Inactive |
| SEALIFE SIBLINGS, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 27, 2015 | Inactive |
| POPS STIGLITZ SCHOLARSHIP FUND INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Mar 15, 2016 | Inactive |
| KEYS CHRISTIAN ACADEMY INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Jun 28, 2016 | Inactive |
| THE SHAMROCK CLUB, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Aug 9, 2016 | Inactive |
| KEY TRAILER COURT HOMEOWNERS ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Aug 6, 1986 | Inactive |
| THE 96 CORPORATIONMarathon, FL · Inactive | Marathon, FL | Nonprofit | Dec 19, 2016 | Inactive |
| GALWAY BAY MOBILE HOMEOWNERS ASSOCIATION, INC.Marathon Monroe County, FL · Active | Marathon Monroe County, FL | Nonprofit | Apr 7, 2017 | Active |
| LOCAL SOUL INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 10, 2017 | Inactive |
| KEYS TO RESTORATION INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Sep 18, 2017 | Inactive |
| AMERICAN CARIBBEAN CHARITABLE TRUST INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 16, 2017 | Inactive |
| THE REEF AT MARATHON RESORT CLUB II CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Sep 29, 1986 | Active |
| COCO PLUM BEACH YACHT CLUB CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Sep 30, 1986 | Active |
| MARATHON LUTHERAN SCHOOL,INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 23, 2018 | Inactive |
| BRUCE'S LEARNING CENTER INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Aug 23, 2018 | Inactive |
| FLORIDA KEYS DROWNING PREVENTION TASK FORCE INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Nov 20, 2018 | Inactive |
| THE MARTIN LUTHER CHAPEL FOUNDATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Dec 11, 1986 | Inactive |
| MARATHON LUTHERAN SCHOOL INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Jan 23, 1987 | Inactive |
| FLORIDA KEYS BIBLE COLLEGE INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Jan 22, 2019 | Inactive |
| THE BLONDE AND THE BULLIES INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Mar 1, 2019 | Inactive |
| FLORIDA KEYS NON PROFITS INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 22, 2019 | Inactive |
| FLORIDA KEYS VEGAN COMMUNITY, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 10, 2019 | Inactive |
| COMPANION CARE FUND CORPORATIONMarathon, FL · Inactive | Marathon, FL | Nonprofit | May 28, 2019 | Inactive |
| THE SHORES AT COCO PLUM CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Jan 30, 1987 | Active |
| MARATHON SAILING CLUB, INC.Duck Key, FL · Inactive | Duck Key, FL | Nonprofit | Feb 3, 1987 | Inactive |
| WILD OLIVE MISSIONS INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Feb 17, 2020 | Inactive |
| FAITH FIVE 2, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Mar 9, 2020 | Inactive |
| SOMBRERO RESORT CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Apr 24, 1987 | Active |
| MARATHON PRESBYTERIAN CHURCH INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Feb 16, 2021 | Inactive |
| MAKO AUTOMOTIVE RESEARCH INSTITUTE INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Mar 1, 2021 | Inactive |
| FLORIDA KEYS EHLERS DANLOS SOCIETY INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 13, 2021 | Inactive |
| DUCK KEY FISHING CLUB, INC.Duck Key, FL · Inactive | Duck Key, FL | Nonprofit | Dec 13, 2021 | Inactive |
| OCEAN ON THE OCEAN, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Dec 21, 2021 | Inactive |
| N9596W FLYING CLUB CORP.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 21, 2022 | Inactive |
| SEAGLASS FLATS HOMEOWNERS' ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 27, 2022 | Inactive |
| MARATHON DOLPHINS YOUTH PROGRAM INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Jun 16, 2022 | Inactive |
| FLORIDA KEYS OCEANEERS INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Jul 11, 2022 | Inactive |
| KEEP IT IN THE KEYS INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Aug 12, 2022 | Inactive |
| YATZ HOUSE OF HOPE MINISTRIES INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Nov 14, 2022 | Inactive |
| COCO PLUM CENTRAL DISPOSAL SYSTEMS, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 1, 1987 | Inactive |
| TROPIC ISLE SUBDIVISION HOMEOWNERS ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 9, 1987 | Inactive |
| SOMBRERO ISLE LANDSCAPING FUND CORP.Marathon, FL · Active | Marathon, FL | Nonprofit | Nov 13, 2023 | Active |
| SAN PABLO CATHOLIC PARISH IN MARATHON, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Dec 11, 2023 | Active |
| SUSTAINABLE OCEAN AND REEFS INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Jun 27, 2024 | Active |
| SAVING JANE INC.Location not reported, FL · Inactive | Location not reported, FL | Nonprofit | Aug 6, 2024 | Inactive |
| FLORIDA KEYS & KEY WEST FOUNDATION, INCMarathon, FL · Inactive | Marathon, FL | Nonprofit | Nov 25, 2024 | Inactive |
| TESTIMONY OF GRACE MISSION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Dec 31, 1987 | Inactive |