| LDLitchfield Distillery | Litchfield | CT | Beverage and Tobacco Product Manufacturing312140 | — | ◐ LIKELY ACTIVE |
| LPLitchfield Prime Meats & Provisions LLC | Litchfield | CT | Food Manufacturing311612 | — | ◐ LIKELY ACTIVE |
| LMLittle Meadow Farm | Redding | CT | Beverage and Tobacco Product Manufacturing312140 | — | ◐ LIKELY ACTIVE |
| LCLiuzzi Cheese | Hamden | CT | Food Manufacturing311513 | 100-499 | ◐ LIKELY ACTIVE |
| LMLockheed Martin Corporation US CT Bridgeport South Ave (5220) | Bridgeport | CT | Transportation Equipment Manufacturing336411 | 100-499 | ◐ LIKELY ACTIVE |
| LMLockheed Martin Corporation US CT Stratford Main St (5225) | Stratford | CT | Transportation Equipment Manufacturing336411 | 500+ | ◐ LIKELY ACTIVE |
| LMLockheed Martin Corporation US CT Trumbull (5227) | Trumbull | CT | Transportation Equipment Manufacturing336411 | 100-499 | ◐ LIKELY ACTIVE |
| LSLogo Sportswear Inc - Wallingford | Wallingford | CT | Printing and Related Support Activities323113 | 100-499 | ◐ LIKELY ACTIVE |
| LVLong View Ciderhouse | Southington | CT | Beverage and Tobacco Product Manufacturing312130 | — | ◐ LIKELY ACTIVE |
| LCLoos & Co., Inc. Pomfret | Pomfret Center | CT | Primary Metal Manufacturing331222 | 100-499 | ◐ LIKELY ACTIVE |
| LALost Acres Vineyard | North Granby | CT | Beverage and Tobacco Product Manufacturing312130 | — | ◐ LIKELY ACTIVE |
| LILuchs INC | Greenwich | CT | Machinery Manufacturing333310 | — | ◐ LIKELY ACTIVE |
| MOMain Office | Naugatuck | CT | Wood Product Manufacturing321918 | 20-99 | ◐ LIKELY ACTIVE |
| MManchester | Manchester | CT | Printing and Related Support Activities323111 | 20-99 | ◐ LIKELY ACTIVE |
| MPManchester Packing Co., Inc. | Hartford | CT | Food Manufacturing311612 | — | ◐ LIKELY ACTIVE |
| MOMan of Steel Welding Services LLC | Seymour | CT | Fabricated Metal Product Manufacturing332323 | — | ◐ LIKELY ACTIVE |
| MManufacturing | Berlin | CT | Machinery Manufacturing333514 | 20-99 | ◐ LIKELY ACTIVE |
| MLMarjor LLC | Hartford | CT | Beverage and Tobacco Product Manufacturing312140 | — | ◐ LIKELY ACTIVE |
| MVMclaughlin Vineyards INC. | Sandy Hook | CT | Beverage and Tobacco Product Manufacturing312130 | — | ◐ LIKELY ACTIVE |
| MCM Cubed Technology Incorporated | Newtown | CT | Nonmetallic Mineral Product Manufacturing327110 | 20-99 | ◐ LIKELY ACTIVE |
| MPMcWane Plant & Industrial - Wethersfield | Wethersfield | CT | Fabricated Metal Product Manufacturing332996 | 1-19 | ◐ LIKELY ACTIVE |
| MMMelvin Mayo | Enfield | CT | Miscellaneous Manufacturing339950 | — | ◐ LIKELY ACTIVE |
| MNMeriden Novolex Plant | Meriden | CT | Paper Manufacturing322220 | 20-99 | ◐ LIKELY ACTIVE |
| MUMetals USA - Gregor Technologies | Torrington | CT | Fabricated Metal Product Manufacturing332710 | 20-99 | ◐ LIKELY ACTIVE |
| MHMfs Holdings Incorporated | Stafford Springs | CT | Fabricated Metal Product Manufacturing332710 | — | ◐ LIKELY ACTIVE |
| MTMicrochip Technology Inc. Simsbury | Simsbury | CT | Computer and Electronic Product Manufacturing334413 | 20-99 | ◐ LIKELY ACTIVE |
| MAMicromod Automation & Controls LLC | Cromwell | CT | Computer and Electronic Product Manufacturing334513 | — | ◐ LIKELY ACTIVE |
| MCMicrosemi CORP. - Rf Signal Processing | Simsbury | CT | Computer and Electronic Product Manufacturing334419 | — | ◐ LIKELY ACTIVE |
| MMilford | Milford | CT | Transportation Equipment Manufacturing336390 | 100-499 | ◐ LIKELY ACTIVE |
| MMMillers Manufacturing LLC | North Franklin | CT | Fabricated Metal Product Manufacturing332999 | — | ◐ LIKELY ACTIVE |
| MIMillwood, Inc. North Haven | North Haven | CT | Wood Product Manufacturing321920 | 20-99 | ◐ LIKELY ACTIVE |
| MMMini Melts USA -Norwich Depot | Norwich | CT | Food Manufacturing311520 | 20-99 | ◐ LIKELY ACTIVE |
| MMMinore's Meats, LLC | New Haven | CT | Food Manufacturing311612 | — | ◐ LIKELY ACTIVE |
| MIMinteq International | Canaan | CT | Primary Metal Manufacturing331491 | 20-99 | ◐ LIKELY ACTIVE |
| MNMk North America, INC. | Bloomfield | CT | Machinery Manufacturing333922 | 100-499 | ◐ LIKELY ACTIVE |
Monroe Engineering Group LLC | North Branford | CT | Fabricated Metal Product Manufacturing332618 | 20-99 | ◐ LIKELY ACTIVE |
| MHMoose Hill Cider LLC | Oxford | CT | Beverage and Tobacco Product Manufacturing312130 | — | ◐ LIKELY ACTIVE |
| MEMorin East | Bristol | CT | Fabricated Metal Product Manufacturing332322 | 20-99 | ◐ LIKELY ACTIVE |
| MmPulse | Stratford | CT | Printing and Related Support Activities323111 | 20-99 | ◐ LIKELY ACTIVE |
| NCNatural Country Farms-Ellington | Ellington | CT | Food Manufacturing311411 | 100-499 | ◐ LIKELY ACTIVE |
| NBNew Britain Hand Tools, Stanley Black & Decker | New Britain | CT | Fabricated Metal Product Manufacturing332216 | 100-499 | ◐ LIKELY ACTIVE |
| NENew England Asphalt Services LLC | Northford | CT | Petroleum and Coal Products Manufacturing324121 | — | ◐ LIKELY ACTIVE |
| NGNewtown Granite Works | Newtown | CT | Nonmetallic Mineral Product Manufacturing327991 | 1-19 | ◐ LIKELY ACTIVE |
| NGNext Generation Construction, LLC | Stratford | CT | Fabricated Metal Product Manufacturing332323 | — | ◐ LIKELY ACTIVE |
| NNgsp-y798 | East Hartford | CT | Transportation Equipment Manufacturing336413 | 100-499 | ◐ LIKELY ACTIVE |
| NBNiagara Bottling, LLC - Bloomfield | Bloomfield | CT | Beverage and Tobacco Product Manufacturing312112 | 20-99 | ◐ LIKELY ACTIVE |
| NNNit Noi Provisions | Norwalk | CT | — | — | ◐ LIKELY ACTIVE |
| NMNoack's Meat Products, Inc. | Meriden | CT | Food Manufacturing311612 | — | ◐ LIKELY ACTIVE |
| NMNordic Moon Meadery | Ellington | CT | Beverage and Tobacco Product Manufacturing312130 | — | ◐ LIKELY ACTIVE |
| NHNorth Haven | North Haven | CT | Chemical Manufacturing325120 | 20-99 | ◐ LIKELY ACTIVE |