| WINSLOW ELECTRIC COMPANY THEOld Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Sep 18, 1972 | Dissolved |
| BEL-AIRE MANOR BEACH ASSOCIATION, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Jul 11, 1974 | Active |
| BLUEBERRY LANE RESIDENTS ASSOCIATION, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Apr 26, 1974 | Active |
| CHESTNUT HILL CONCERTS, INCORPORATEDOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Jan 21, 1970 | Active |
| CONNECTICUT BUS ASSOCIATION, INC. THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Oct 27, 1922 | Active |
| CORNFIELD POINT BEACH CLUB INCORPORATED, THEOld Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Jun 30, 1934 | Dissolved |
| COVE CONDOMINIUM ASSOCIATION, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Oct 14, 1976 | Active |
| EDUCATION & RESEARCH SYSTEMS, INC.Old Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Mar 7, 1977 | Dissolved |
| ESTUARY COUNCIL OF SENIORS, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Nov 26, 1974 | Active |
| THE EXCHANGE CLUB OF OLD SAYBROOK-WESTBROOK, CONNECTICUT, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Mar 30, 1971 | Active |
| GLEN ASSOCIATION OF OLD SAYBROOK CT. INC. THEOld Saybrook, CT · Forfeited | Old Saybrook, CT | Corporation | Oct 24, 1960 | Forfeited |
| OLD SAYBROOK FOUNDATION, INC., THEOld Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Apr 4, 1972 | Dissolved |
| TOM & CLAIRE O'NEIL FOUNDATION, INC., THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Dec 28, 1954 | Active |
| LSW, INC.Old Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Apr 4, 1972 | Dissolved |
| MIDDLESEX/SHORELINE ASSOCIATION OF REALTORS, INC.Old Saybrook, CT · Merged | Old Saybrook, CT | Corporation | May 22, 1963 | Merged |
| NEW HAVEN RAILROAD HISTORICAL AND TECHNICAL ASSOCIATION, INCORPORATED, THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Mar 14, 1977 | Active |
| NORTH COVE YACHT CLUB, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Jul 16, 1969 | Active |
| OLD SAYBROOK CHAMBER OF COMMERCE, INCORPORATED, THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Oct 6, 1960 | Active |
| OLD SAYBROOK FIRE COMPANY NO 1 INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Aug 27, 1963 | Active |
| OLD SAYBROOK FIRE COMPANY NO. 1, INC., THEOld Saybrook, CT · Merged | Old Saybrook, CT | Corporation | Dec 12, 1951 | Merged |
| OLD SAYBROOK MEMORIAL POST, POST NO. 10153 VETERANS OF FOREIGN WARS OF THE UNITED STATES, INCORPORATOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Apr 23, 1973 | Active |
| OLD SAYBROOK HISTORICAL SOCIETY, INCORPORATED, THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Jan 19, 1959 | Active |
| OLD SAYBROOK LIONS CLUB, INCORPORATED, THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Apr 28, 1958 | Active |
| OTTER COVE ASSOCIATION, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Apr 7, 1965 | Active |
| RESERVOIR BEACH IMPROVEMENT ASSOCIATION, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Jun 2, 1969 | Active |
| SAYBROOK MANOR COVE ASSOCIATION, INCORPORATEDOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Aug 22, 1956 | Active |
| CONNECTICUT PACKAGE STORES ASSOCIATION, INCORPORATEDOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Sep 13, 1943 | Active |
| CONNECTICUT PSYCHOLOGICAL ASSOCIATION, INCORPORATED, THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Feb 28, 1946 | Active |
| FAULK-MARCOLINI POST 113 AMERICAN LEGION, INCORPORATEDOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Jul 1, 1929 | Active |
| SAYBROOK COMMUNITY CHURCH, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Nov 24, 1972 | Active |
| CONNECTICUT MARINE INSTRUMENT CO., INC.Old Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Sep 12, 1977 | Dissolved |
| JIFFY, INC.Old Saybrook, CT · Forfeited | Old Saybrook, CT | Corporation | Dec 5, 1977 | Forfeited |
| ROBERT L. DAY CO., INC.Old Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Dec 30, 1977 | Dissolved |
| NYMAN JEWELERS, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Jan 19, 1978 | Active |
| COLE INSURANCE AGENCY, INC.Old Saybrook, CT · Forfeited | Old Saybrook, CT | Corporation | Mar 28, 1978 | Forfeited |
| TECHNICAL INSIGHTS, INC.Old Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Mar 29, 1978 | Dissolved |
| NORTHEAST MEDICAL PRODUCTS, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | May 15, 1978 | Active |
| U. S. PROLAM, INC.Old Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Jun 12, 1978 | Dissolved |
| LHI, INCORPORATEDOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Mar 5, 1956 | Active |
| BREWSTER CORPORATION THEOld Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Jun 5, 1953 | Dissolved |
| RYTHER-PURDY LUMBER COMPANY, INC. THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Mar 28, 1977 | Active |
| MAIN & ELM CORPORATIONOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Jan 30, 1979 | Active |
| ESSEX WINTER SERIES, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Feb 15, 1979 | Active |
| E.W. HANNAS, INC.Old Saybrook, CT · Forfeited | Old Saybrook, CT | Corporation | Jun 12, 1979 | Forfeited |
| BARN CONDOMINIUM ASSOCIATION, INC. THEOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Aug 16, 1979 | Active |
| JOHN T. CARROLL, D.P.M., P.C.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Oct 1, 1979 | Active |
| OLD SAYBROOK SENIOR HOUSING, INCORPORATEDOld Saybrook, CT · Active | Old Saybrook, CT | Corporation | Oct 18, 1979 | Active |
| TARGET CUSTOM MANUFACTURING, INC.Old Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Nov 8, 1979 | Dissolved |
| NATIONAL ALARM SERVICES, INC.Old Saybrook, CT · Dissolved | Old Saybrook, CT | Corporation | Nov 19, 1979 | Dissolved |
| EASTERN ANALYTICAL LABORATORY, INC.Old Saybrook, CT · Active | Old Saybrook, CT | Corporation | Dec 6, 1979 | Active |