| Countrywide Sales and Marketing Limited | Wholesale & retail | 2006 |
| Countrywide Travel Limited | Transport & logistics | 2007 |
| County Architectural Ironmongery Limited | Wholesale & retail | 1988 |
| County Building & Maintenance Limited | Construction | 2022 |
| County Care Northampton Limited | Health & social care | 2023 |
| County Carpets Limited | Construction | 2017 |
| County Cars (Northampton) Ltd | Transport & logistics | 2016 |
| County Civil Engineering Ltd | Construction | 2025 |
| County Clean Ltd | Administrative & support | 2017 |
| County Construct and Maintain Limited | Construction | 2007 |
| County Conversions Ltd | Construction | 2016 |
| County Cooling Ltd | Construction | 2025 |
| County Fabrications (Leicester) Limited | Manufacturing | 2010 |
| County Footwear Sales and Marketing | | 1993 |
| County Fostering Services Ltd | Administrative & support | 2018 |
| County Leasing Limited | Financial services | 1985 |
| County Pride Products Limited | Wholesale & retail | 1947 |
| County Pumps Northants Limited | Manufacturing | 2025 |
| County Specialists Limited | Administrative & support | 2015 |
| County Surveys Limited | Professional & scientific | 2022 |
| Countynet Holdings Limited | Financial services | 2025 |
| Countynet Limited | Information & communication | 2011 |
| Countywide Landscapes Limited | Administrative & support | 2015 |
| Couriergram Ltd. | Transport & logistics | 2004 |
| Couriergram Nationwide Telegram Service Ltd. | Transport & logistics | 1982 |
| Couriers RX7 Ltd | Transport & logistics | 2025 |
| Court Surfaces Ltd | Construction | 2012 |
| Courteenhall Limited | Real estate | 2015 |
| Courtland Dental Centre Limited | Health & social care | 2012 |
| Courtleigh (Bridge Lane) Limited | Households | 2003 |
| Cova 4 Limited | Transport & logistics | 2017 |
| Covefy Ltd | Wholesale & retail | 2023 |
| Covent Garden Brokers Limited | Real estate | 1995 |
| Covent Garden Hardware Store Ltd | Hospitality | 2021 |
| Covergold Limited | Manufacturing | 1992 |
| Covert Electronics Limited | Manufacturing | 2025 |
| Cowalk Construction Ltd | Manufacturing | 2024 |
| Cowan Driving School Ltd | Education | 2016 |
| Cowley 2 Renewables Ltd | Professional & scientific | 2023 |
| Cowley 7 Renewables Ltd | Professional & scientific | 2023 |
| COX & Collier Developments Ltd | Construction | 2013 |
| Coycom Limited | Administrative & support | 2014 |
| Coyds International Limited | Professional & scientific | 2004 |
| Cozma MD Ltd | Construction | 2020 |
| Cozmintrans Limited | Transport & logistics | 2026 |
| Cozy Cribbs SA Ltd | Hospitality | 2022 |
| Cozy Nursery Ltd | Wholesale & retail | 2020 |
| Cozynest Accomodation Ltd | Real estate | 2017 |
| CP Lawrence Livestock Ltd | Agriculture & fishing | 2023 |
| CP Thermal Engineering Ltd | Construction | 2017 |
| CPA Build & Joinery Ltd | Construction | 2026 |
| CPB Civils Ltd | Construction | 2015 |
| CPL Aromas (Holdings) Limited | Manufacturing | 1999 |
| CPL Aromas Limited | Manufacturing | 1971 |
| CPO Northampton Ltd | Professional & scientific | 2025 |
| CPQ Support Services Ltd | Information & communication | 2021 |
| CPS Construct Ltd | Construction | 2022 |
| CR Brick and Stonework Ltd | Construction | 2021 |
| CR Housing Developments Limited | Construction | 2024 |
| CR Management (Services) Limited | Professional & scientific | 2013 |
| CR Transporter Ltd | Transport & logistics | 2025 |
| Crabs in a Bucket Ltd | Wholesale & retail | 2025 |
| Craddocks Bakery Ltd | Wholesale & retail | 2018 |
| Cradley Special Brick Company Limited | Extraterritorial | 2016 |
| Craft 786 Code Ltd | Information & communication | 2024 |
| Craft Beer Cellar Ltd | Wholesale & retail | 2020 |
| Craft Energy Ltd | Transport & logistics | 2025 |
| Craft Haven UK Design Ltd | Professional & scientific | 2026 |
| Craft LUX Ltd | Construction | 2019 |
| Craft-Art Ltd | Construction | 2019 |
| Crafted Barber Company Ltd | Other services | 2026 |
| Crafted Gifts Atelier Limited | Manufacturing | 2022 |
| Craftyv Co Hub Ltd | Wholesale & retail | 2025 |
| Craig Allen Marine Limited | Transport & logistics | 2008 |
| Cranberry Networks Ltd | Information & communication | 2017 |
| Crane Plastics Limited | Manufacturing | 2008 |
| Cranehill Engineering & Plant Repairs Limited | Agriculture & fishing | 2006 |
| Craneview EM Ltd | Construction | 2016 |
| Cranford Asset Management Limited | Agriculture & fishing | 2023 |
| Crasco Ltd | Construction | 2023 |
| Craven Management Company Limited | Households | 1988 |
| Cray Smith Limited | Information & communication | 2021 |
| Crazy for Christmas Limited | Manufacturing | 2025 |
| CRD Drain Solutions Ltd | Administrative & support | 2024 |
| Crdc Limited | Professional & scientific | 2004 |
| CRE8 Solutions Management Ltd | Financial services | 2023 |
| CRE8CHANGE CIC | Education | 2023 |
| Create a Gift Limited | Wholesale & retail | 2003 |
| Create Bespoke Interiors Limited | Manufacturing | 2016 |
| Create Music Ltd | Education | 2018 |
| CREATED2FIT Group Ltd | Wholesale & retail | 2025 |
| Creating Equalz | Education | 2017 |
| Creation Enterprises Limited | Professional & scientific | 2019 |
| Creation Reprographics Limited | Manufacturing | 2006 |
| Creation Systems & Associates Limited | Information & communication | 2012 |
| Creations London Limited | Manufacturing | 2009 |
| Creative Application Limited | Information & communication | 2016 |
| Creative Chic Ltd | Arts & recreation | 2018 |
| Creative Code Logic Limited | Information & communication | 2026 |
| Creative Edge (Northampton) Limited | Construction | 2015 |