| Car Salvage Ltd | Administrative & support | 2008 |
| Car Therapy Detailing Ltd | Extraterritorial | 2020 |
| Carlton 100 Ltd | Hospitality | 2025 |
| Carter and Dean Plumbing and Heating Ltd | Construction | 2024 |
| Carter Transport Limited | Transport & logistics | 2026 |
| Carter-Lloyd Properties Ltd | Real estate | 2025 |
| CAS GAS Limited | Wholesale & retail | 2024 |
| Casa Project Solutions Ltd | Construction | 2026 |
| Castle & Co Accountants Limited | Professional & scientific | 2013 |
| Castle Building Services Ltd | Manufacturing | 2016 |
| Castle Dwellings Ltd | Real estate | 2006 |
| Castle Motorcycles Limited | Wholesale & retail | 2009 |
| Castle Parade Store Ltd | Wholesale & retail | 2024 |
| Castle Water Bathrooms Ltd | Wholesale & retail | 2017 |
| Castleford Academy Trading Limited | Administrative & support | 2011 |
| Castleford Academy Trust | Education | 2011 |
| Castleford Bearings Limited | Wholesale & retail | 2010 |
| Castleford Boat Yard Limited | Other services | 2014 |
| Castleford Boxing Academy CIC | Education | 2025 |
| Castleford Caravan & Self Storage Ltd | Transport & logistics | 2025 |
| Castleford Carwash Limited | Wholesale & retail | 2017 |
| Castleford Catering Limited | Hospitality | 2017 |
| Castleford Cooling Services Ltd | Manufacturing | 2023 |
| Castleford Engineering Services Ltd | Professional & scientific | 2021 |
| Castleford Express Market Limited | Wholesale & retail | 2025 |
| Castleford Food Supplies Limited | Hospitality | 2023 |
| Castleford Fuels Ltd | Wholesale & retail | 2026 |
| Castleford Furniture and Carpet Centre Ltd | Manufacturing | 2018 |
| Castleford Grab & Go Ltd | Wholesale & retail | 2025 |
| Castleford Hair & Beauty Training CIC | Education | 2025 |
| Castleford Hand Car Wash Limited | Other services | 2020 |
| Castleford Heritage Trust | Other services | 2004 |
| Castleford JV Holdings Limited | Financial services | 2017 |
| Castleford JV Limited | Wholesale & retail | 2013 |
| Castleford Management Limited | Other services | 2019 |
| Castleford Masonic Hall Company,Limited | Hospitality | 1902 |
| Castleford Mobile Zone Limited | Wholesale & retail | 2023 |
| Castleford Physiotherapy Limited | Other services | 2020 |
| Castleford Retail Ltd | Transport & logistics | 2016 |
| Castleford Rugby League Football Club Limited(The) | Arts & recreation | 1926 |
| Castleford Scaffolding Services Ltd | Construction | 2023 |
| Castleford Slicing Company Limited | Wholesale & retail | 2008 |
| Castleford Town Centre Partnership Limited | Professional & scientific | 2003 |
| Castleford Trailers Ltd | Administrative & support | 2023 |
| Castleford White Rose Optical Limited | Wholesale & retail | 2025 |
| Castlefordchippy Ltd | Hospitality | 2026 |
| Castlegate Food Limited | Wholesale & retail | 2022 |
| Castlepoint Cleaning Services Ltd | Administrative & support | 2024 |
| CBR Engineering Limited | Manufacturing | 2003 |
| CCL Syrinx (UK Holding) Limited | Extraterritorial | 2017 |
| CCL Syrinx (UK) Limited | Financial services | 2016 |
| CD Plumbing Ltd. | Construction | 2019 |
| Centennial Park Management Company Limited | Construction | 2005 |
| Centre Service Limited | Wholesale & retail | 1981 |
| Cephalon (UK) Limited | Wholesale & retail | 1996 |
| CEY Property Ltd | Construction | 2026 |
| Chakaz Limited | Health & social care | 2013 |
| Chameleonclean Ltd | Administrative & support | 2025 |
| Chana Brother Properties Ltd | Real estate | 2023 |
| Change Appetite Ltd | Wholesale & retail | 2021 |
| Chapel Street (Bankside Works) Management Company Limited | Households | 2021 |
| Chapter Rooms Ltd | Hospitality | 2021 |
| Chaston Standard Limited | Wholesale & retail | 1998 |
| Chaudhary Castleford Ltd | Hospitality | 2026 |
| Checkstone Security Limited | Administrative & support | 2025 |
| Chengda Limited | Hospitality | 2023 |
| Chequerfield Ltd | Hospitality | 2025 |
| Chicks With Bricks Ltd | Real estate | 2024 |
| Chihota Enterprises Ltd | Wholesale & retail | 2025 |
| Chinese Kwokbo Ltd | Wholesale & retail | 2024 |
| Chiorino U.K. Limited | Manufacturing | 1975 |
| Chippycarlton Ltd | Hospitality | 2025 |
| Chloe Marks Psychology Limited | Health & social care | 2025 |
| Choudhrys Real Estate Company Ltd | Construction | 2017 |
| Chris Carr Building Services Limited | Construction | 2023 |
| Christart JAN Ltd | Transport & logistics | 2024 |
| Christie Fields (Greater Estate) Management Company Limited | Real estate | 2007 |
| Christie Fields Management Company Limited | Real estate | 2006 |
| Chuen HOI Wholesale Ltd | Wholesale & retail | 2026 |
| Circle Control & Design Systems Limited | Construction | 1995 |
| Cirrus Laminations Limited | Real estate | 2005 |
| City Fields Transport Ltd | Professional & scientific | 2024 |
| Citylogic Computer Services Limited | Information & communication | 1995 |
| CJD8013 Ltd | Hospitality | 2026 |
| CJG Automotive Ltd | Wholesale & retail | 2025 |
| CK Hutchinson Group Limited | Hospitality | 2025 |
| CKZ Properties Ltd | Real estate | 2022 |
| Class Haus Limited | Wholesale & retail | 2026 |
| Classic Building Developments Limited | Construction | 2024 |
| Classic Glazing Holdings Limited | Financial services | 2023 |
| Claytons Barbershop Ltd | Other services | 2023 |
| CLD Accounting Limited | Professional & scientific | 2025 |
| Cleanscene Elite Ltd | Wholesale & retail | 2025 |
| Clever Stuff (International) Ltd | Wholesale & retail | 1998 |
| Clinic 65 Ltd | Other services | 2020 |
| Clinicare Care Home Services Ltd | Wholesale & retail | 2025 |
| CLM Transport Ltd | Transport & logistics | 2017 |
| CLO Amazon Shop Limited | Wholesale & retail | 2025 |
| CLO DM Limited | Professional & scientific | 2022 |
| CLO PG Limited | Financial services | 2022 |