| THE FIRST PROFESSIONAL CENTRE CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Sep 25, 1978 | Active |
| MARINA CONDOMINIUM APARTMENTS, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Oct 30, 1978 | Active |
| MARATHON VOL. FIRE AND RESCUE, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Apr 27, 1979 | Active |
| FLAMINGO ISLAND PROPERTY OWNERS ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | May 21, 1979 | Active |
| MARATHON FRIENDS OF ANIMALS, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Sep 25, 1979 | Inactive |
| MARATHON LIONS CLUB, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 16, 1979 | Inactive |
| SOMBRERO ISLE PROPERTY OWNERS ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Nov 14, 1979 | Inactive |
| FLORIDA KEYS CONCERT ASSOCIATION, INCMarathon, FL · Active | Marathon, FL | Nonprofit | Jan 11, 1980 | Active |
| MARATHON SAIL AND POWER SQUARDON, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Feb 18, 1980 | Active |
| CONSUMERS OPPOSED TO WASTE, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 28, 1980 | Inactive |
| FRIENDS OF THE MARATHON LIBRARY, INC.Duck Key, FL · Inactive | Duck Key, FL | Nonprofit | Dec 30, 1980 | Inactive |
| PIRATES COVE I CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Jan 29, 1981 | Active |
| BONEFISH YACHT CLUB HOMEOWNERS ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Feb 20, 1981 | Active |
| THE FLORIDA KEYS MEDICAL COMPLEX CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Mar 6, 1981 | Inactive |
| SUNSET COURTS CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Mar 24, 1981 | Active |
| DOMESTIC ABUSE SHELTER, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Mar 24, 1981 | Active |
| DOLPHIN RESEARCH CENTER, INC.Grassy Key, FL · Active | Grassy Key, FL | Nonprofit | Mar 25, 1981 | Active |
| FLORIDA KEYS CITIZENS COALITION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Apr 3, 1981 | Active |
| COCO PLUM BEACH PROPERTY OWNERS ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | May 6, 1981 | Active |
| MARATHON YACHT CLUB, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | May 18, 1981 | Active |
| OCEAN ISLES FISHING VILLAGE, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | May 18, 1981 | Active |
| STIRRUP KEY CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Jul 22, 1981 | Active |
| KEYS INDEPENDENT FISHERMEN'S CO-OP INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Aug 21, 1981 | Active |
| GULFPOINTE CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Sep 8, 1981 | Active |
| SEAWATCH AT MARATHON CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Sep 29, 1981 | Active |
| COMMUNITY COOPERATIVE PRESCHOOL, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Sep 29, 1981 | Active |
| FLORIDA KEYS CONTRACTORS ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 14, 1981 | Inactive |
| MARATHON KEY BEACH CLUB II ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Nov 3, 1981 | Active |
| FARO BLANCO CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Nov 16, 1981 | Active |
| CAPTAIN'S QUARTERS CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Jan 7, 1982 | Active |
| TREASURE CAY CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Jan 12, 1982 | Active |
| BONEFISH MARINA CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Jun 1, 1982 | Active |
| THE REEF AT MARATHON CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Mar 12, 1982 | Active |
| MARATHON RUNNERS CLUB, INC.Marathon, FL · Active | Marathon, FL | Nonprofit | Apr 26, 1982 | Active |
| COCOPLUM YACHT AND BEACH CLUB I ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Jun 18, 1982 | Inactive |
| TORTUGA VERANDA CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Aug 19, 1982 | Inactive |
| LA KASSARINE CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 5, 1982 | Inactive |
| THE MARATHON HIGH SCHOOL BOOSTERS CLUB, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Oct 7, 1982 | Inactive |
| GALWAY BAY TENANTS ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Mar 24, 1983 | Inactive |
| LA TROPIQUE CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 13, 1983 | Inactive |
| BIG PINE GARAGES CONDOMINIUM ASSOCIATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Apr 21, 1983 | Inactive |
| MONROE COUNTY SHERIFF'S RESERVE, MARATHON SUB-STATION, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Jun 1, 1983 | Inactive |
| CASA DE LOS TRES, A CONDOMINIUM, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Aug 23, 1983 | Inactive |
| FLORIDA KEYS FISHERMEN'S COOPERATIVE, INC.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Jul 5, 1977 | Inactive |
| DRIFTWAY REALTY CO., INC.Marathon, FL · Inactive | Marathon, FL | Corporation | Jun 10, 1971 | Inactive |
| GENERAL PRODUCTS SALES CORPORATIONDuck Key, FL · Inactive | Duck Key, FL | Corporation | Jul 31, 1974 | Inactive |
| TRANSPORT INVESTMENTS CORP.Marathon, FL · Inactive | Marathon, FL | Nonprofit | Aug 17, 1979 | Inactive |
| MARATHON PROPERTIES, LLLPMarathon, FL · Inactive | Marathon, FL | Partnership | May 10, 2000 | Inactive |
| NURSING HOME MANAGEMENT, LTD.Marathon, FL · Inactive | Marathon, FL | Partnership | Sep 5, 2003 | Inactive |
| TARPON LODGE LIMITED PARTNERSHIPMarathon, FL · Inactive | Marathon, FL | Partnership | Feb 27, 1975 | Inactive |