| Northraven Properties Limited | Real estate | 2023 |
| Northreach Logistics Ltd | Transport & logistics | 2025 |
| Northridge Healthcare Limited | Health & social care | 2010 |
| Northside Farms Limited | Hospitality | 2024 |
| Northside Insulation Limited | Construction | 1998 |
| Northsouth Consultants Ltd | Professional & scientific | 2024 |
| Northstandard Group Services Limited | Administrative & support | 2000 |
| Northstandard Limited | Financial services | 1952 |
| Northstar Audio Visual Limited | Arts & recreation | 2015 |
| Northstar Equity Investors Limited | Extraterritorial | 2011 |
| Northstar Feline Care Ltd | Other services | 2026 |
| Northstar Innovation Limited | Financial services | 2016 |
| Northstar Nominees Limited | Extraterritorial | 2023 |
| Northstar Pet Care Ltd | Financial services | 2025 |
| Northstar Retail Ltd | Wholesale & retail | 2021 |
| Northstar Ventures Group Limited | Financial services | 2015 |
| Northstar Ventures Holdings Limited | Financial services | 2015 |
| Northstar Ventures Limited | Financial services | 2004 |
| Northstay Living Holding Ltd | Hospitality | 2026 |
| Northstone Living Ltd | Hospitality | 2026 |
| Northumberland & Durham Property Trust Limited | Construction | 1922 |
| Northumberland Air Conditioning Ltd | Energy | 2026 |
| Northumberland Antique Centre Limited | Wholesale & retail | 2023 |
| Northumberland Car & Van Centre Limited | Wholesale & retail | 2025 |
| Northumberland Cardiology LLP | | 2019 |
| Northumberland Care Services Ltd | Financial services | 2019 |
| Northumberland Coffee Ltd | Manufacturing | 2022 |
| Northumberland County Recreation Ground Limited(The) | Construction | 1904 |
| Northumberland County Rugby Ltd | Education | 2022 |
| Northumberland Cricket Board Limited | Arts & recreation | 2010 |
| Northumberland Estates Investments Limited | Real estate | 1997 |
| Northumberland Estates Limited | Real estate | 2006 |
| Northumberland Estates Renewables Limited | Energy | 2022 |
| Northumberland Family Butchers Limited | Wholesale & retail | 2022 |
| Northumberland Fine Dining Limited | Hospitality | 2024 |
| Northumberland Getaways Ltd | Real estate | 2021 |
| Northumberland HIP and Knee Ltd | Health & social care | 2019 |
| Northumberland Holidays Limited | Hospitality | 2011 |
| Northumberland Hospitality Limited | Hospitality | 2013 |
| Northumberland Inns Limited | Hospitality | 2024 |
| Northumberland Luxury Lodges Limited | Extraterritorial | 2021 |
| Northumberland Masonic Property Trust Limited | Real estate | 1948 |
| Northumberland Medical Services Limited | Health & social care | 2022 |
| Northumberland Neurorehab Limited | Health & social care | 2014 |
| Northumberland Nook Ltd | Hospitality | 2022 |
| Northumberland Park 3 (Shiremoor) Limited | Real estate | 2011 |
| Northumberland Park Fish & Chip Ltd | Hospitality | 2021 |
| Northumberland Park Management (Shiremoor) Limited | Real estate | 2004 |
| Northumberland Property Investments Limited | Construction | 2008 |
| Northumberland Restaurants Ltd | Hospitality | 2020 |
| Northumberland Rivers Trust | Construction | 2011 |
| Northumberland Square Developments Limited | Construction | 2019 |
| Northumberland Taverns Ltd | Hospitality | 2023 |
| Northumberland Used Vehicles Limited | Wholesale & retail | 2026 |
| Northumbria Accountancy Limited | Professional & scientific | 2016 |
| Northumbria Aerospace Limited T/As NAL Engineering Ltd | Professional & scientific | 2005 |
| Northumbria Classic Car Hire Limited | Administrative & support | 2023 |
| Northumbria Estate Management Ltd | Real estate | 2022 |
| Northumbria European Research LAB Ltd | Education | 2022 |
| Northumbria Finishings Limited | Construction | 2015 |
| Northumbria Forecourts Ltd | Wholesale & retail | 2024 |
| Northumbria GAS Limited | Manufacturing | 2015 |
| Northumbria Group Ltd | Wholesale & retail | 2019 |
| Northumbria Healthcare Facilities Management Limited | Manufacturing | 2012 |
| Northumbria Helicopters Limited | Transport & logistics | 1999 |
| Northumbria International Limited | Education | 2001 |
| Northumbria International School of English Limited | Education | 1978 |
| Northumbria London Campus Limited | Education | 2014 |
| Northumbria Online Limited | Information & communication | 2000 |
| Northumbria Police Sports and Social Club Limited | Arts & recreation | 2002 |
| Northumbria Prestige Limited | Wholesale & retail | 2018 |
| Northumbria Primary Care Limited | Health & social care | 2014 |
| Northumbria Property Developments Ltd | Construction | 2018 |
| Northumbria Property Holdings Ltd | Construction | 2018 |
| Northumbria Radiology LLP | | 2021 |
| Northumbria Students' Union | Hospitality | 2017 |
| Northumbria Technical Services Limited | Other services | 1988 |
| Northumbria University Digital Services Limited | Administrative & support | 2024 |
| Northumbria University Nursery Limited | Education | 2012 |
| Northumbria University Services Limited | Education | 2016 |
| Northumbria Vehicle Co Ltd. | Wholesale & retail | 1999 |
| Northumbrian Leisure Developments Limited | Construction | 2004 |
| Northumbrian Leisure Limited | Hospitality | 1999 |
| Northumbrian Medical Supplies Limited | Wholesale & retail | 2007 |
| Northumbrian Optical Limited | Health & social care | 2010 |
| Northumbrian Pipeline Engineering - Data Ltd | Information & communication | 2025 |
| Northumbrian Sandwich Limited | Hospitality | 2019 |
| Northumbrian Trust Limited | Households | 1986 |
| Northway PEN Properties Ltd | Professional & scientific | 2026 |
| Northwood Tyneside Limited | Real estate | 2003 |
| Norton Gardens Residents Management Company Limited | Real estate | 2019 |
| Norton Park Management Company Limited | Real estate | 2015 |
| Norton Windows and Roofs Limited | Construction | 2021 |
| Norwood Court Maintenance Limited | Households | 1972 |
| Norwood Terrain Services Limited | Administrative & support | 2022 |
| Nosh North East Ltd | Hospitality | 2025 |
| Nosidam Limited | Professional & scientific | 2019 |
| Nostalgia Steel Band and Carnival Club Limited | Education | 1999 |
| Nostobbi Management Ltd | Professional & scientific | 2015 |
| NOT Just a Pretty Face Ltd | Wholesale & retail | 2019 |