| LIN Kitchen Limited | Hospitality | 2020 |
| Ling Dairies Limited | Agriculture & fishing | 2006 |
| Little and Caine Limited | Other services | 2002 |
| Livingstons Solicitors Limited | Professional & scientific | 2007 |
| Local Eats Holdings Limited | Financial services | 2023 |
| Logan Thom Limited | Construction | 2002 |
| Longcourten Developments Limited | Real estate | 1972 |
| Longtown Memorial Hall Community Centre | Education | 2013 |
| Love the Lakes Limited | Wholesale & retail | 2007 |
| Lowis Limited | Administrative & support | 2006 |
| Lowther and Dawson Property Limited | Construction | 1963 |
| Lugus Limited | Real estate | 2000 |
| Lunesdale Learning Trust | Education | 2010 |
| M & D Electrical Distributors (1995) Limited | Wholesale & retail | 1995 |
| M a & J Baird Limited | Agriculture & fishing | 2006 |
| M a Fabrications Ltd | Construction | 2001 |
| M Pearson & SON Limited | Construction | 2005 |
| M W Fisher Agriservices Limited | Agriculture & fishing | 2003 |
| M.J. Young Plumbing Ltd | Construction | 2006 |
| Macbeth, Scott & Co. Life & Pension Services Limited | Financial services | 1973 |
| Mack One Motorsport Limited | Professional & scientific | 2007 |
| Macron Properties Ltd. | Real estate | 2005 |
| MAD Willow Ltd | Real estate | 2026 |
| Magpie Storage Limited | Other services | 2003 |
| Maiden Marine Limited | Wholesale & retail | 1996 |
| Malc Stevens Limited | Construction | 2003 |
| Mark Beverley Joinery Limited | Construction | 2006 |
| Mark Cartwright Decorators Limited | Construction | 2007 |
| Mark Mcguire Limited | Construction | 2003 |
| Mark Roberts (Barrow in Furness) Limited | Wholesale & retail | 2002 |
| Mark Shaw Limited | Construction | 2003 |
| Marl International Holdings Limited | Professional & scientific | 2007 |
| Marl International Limited | Manufacturing | 1973 |
| Marsha LEA Bridal Studio Ltd | Wholesale & retail | 2006 |
| Marten Julian Limited | Extraterritorial | 2003 |
| Martin Dawkins Limited | Construction | 2005 |
| Martin Slader Ltd | Professional & scientific | 2002 |
| Marvins (Penrith) Limited | Wholesale & retail | 2003 |
| Masons Corner Flat Management Company Limited | Households | 2003 |
| Materials Testing Equipment Limited | Construction | 1988 |
| Matson Farms Limited | Agriculture & fishing | 1974 |
| Matthew Keith Limited | Wholesale & retail | 2025 |
| Maxcis Limited | Professional & scientific | 2010 |
| Mcguire Developments Limited | Real estate | 2006 |
| Media Experience Limited | Other services | 2003 |
| Melbreak Developments Ltd | Construction | 2004 |
| Mellbreak Consulting Limited | Information & communication | 2006 |
| Melmore Company Limited | Manufacturing | 2003 |
| Mere Holdings Limited | Financial services | 2023 |
| Mervyn Dicker Limited | Construction | 2006 |
| Messrs Cottam Limited | Agriculture & fishing | 2006 |
| Messrs Ewbank Limited | Agriculture & fishing | 2006 |
| Messrs Holliday Limited | Agriculture & fishing | 2006 |
| Messrs Peile Limited | Agriculture & fishing | 2006 |
| Messrs Ramsay Limited | Agriculture & fishing | 2007 |
| Metcalfe Coaches Limited | Transport & logistics | 1997 |
| Michael Douglas Autosalvage Limited | Wholesale & retail | 2002 |
| Michael Mitchell Dairyman Limited | Wholesale & retail | 2002 |
| Michael Mudd Limited | Manufacturing | 2003 |
| Middleton Wood Company | | 1998 |
| Mike Miller Associates Limited | Manufacturing | 1979 |
| Mike Park Decorating Limited | Construction | 2003 |
| Mike Scott Limited | Construction | 2005 |
| Mill Garage (Frizington) Limited | Wholesale & retail | 2006 |
| Millom Recreation Centre Limited | Arts & recreation | 1990 |
| Millom Workies Limited | Hospitality | 2000 |
| Millstones Development Limited | Wholesale & retail | 2005 |
| Milnthorpe Properties Limited | Real estate | 1963 |
| Mire Services Limited | Hospitality | 2009 |
| MK Hospital International Group Ltd | Professional & scientific | 2012 |
| MM Rigging Services Ltd | Construction | 2016 |
| Modern Homes (Cumbria) Limited | Wholesale & retail | 1999 |
| Modgate Holdings Limited | Financial services | 2020 |
| Modgate Limited | Wholesale & retail | 1978 |
| Modlar Limited | Construction | 1989 |
| Mohair (Hairdressers) Limited | Other services | 2007 |
| Morphet Farms Limited | Hospitality | 2003 |
| Mossops Monumental Masons Limited | Other services | 2002 |
| Mountbarrow Landscapes & Property Maintenance Limited | Other services | 2005 |
| MR. Mister Limited | Wholesale & retail | 2002 |
| MTP Media (2008) Limited | Manufacturing | 2008 |
| Musgraves of Windermere Limited | Wholesale & retail | 1976 |
| Myers & Bowman Limited | Wholesale & retail | 1938 |
| N W Graham & SON Limited | Agriculture & fishing | 2006 |
| NBM Hire Limited | Wholesale & retail | 1996 |
| Neil's Dog Wash Limited | Administrative & support | 2015 |
| Nevinsons Carpets Limited | Wholesale & retail | 2002 |
| New ERA Holdings Limited | Real estate | 1998 |
| New Singkown Limited | Hospitality | 2023 |
| New Visual Solutions Limited | Information & communication | 1999 |
| New Water Lily Limited | Wholesale & retail | 2002 |
| Newton Field Farm | Agriculture & fishing | 2006 |
| Nigel Close Limited | Real estate | 1985 |
| Nixons of Maryport Limited | Wholesale & retail | 2002 |
| Noble Accountants Ltd | Professional & scientific | 2002 |
| Norman Roofing Limited | Construction | 2010 |
| Normandy Properties Limited | Real estate | 2003 |
| North West Consumables Limited | Wholesale & retail | 2002 |
| North West Renovations Limited | Construction | 2003 |
| Nowjet Limited | Professional & scientific | 1988 |