1990–91 Courage League
The 1990–91 National Division One was the fourth season of top flight rugby union in England. The league was expanded to thirteen teams, with promoted teams Northampton Saints and Liverpool St Helens replacing Bedford Blues. Each team played each other once. Bath were the champions, beating Wasps by just one point. Moseley and Liverpool St Helens were relegated.
Participating teams
| Team | Stadium | Capacity | City/Area |
| Bath | Recreation Ground | 8,200 | Bath, Somerset |
| Bristol | Memorial Stadium | 12,100 | Bristol, Avon |
| Gloucester | Kingsholm | 11,000 | Gloucester, Gloucestershire |
| Harlequins | The Stoop | 8,500 | Twickenham, London |
| Leicester Tigers | Welford Road | 16,000 | Leicester, Leicestershire |
| Liverpool St Helens | Moss Lane | St Helens, Merseyside | |
| Moseley | The Reddings | 10,000 | Birmingham, West Midlands |
| Northampton Saints | Franklin's Gardens | 10,000 | Northampton, Northamptonshire |
| Nottingham | Ireland Avenue | 4,950 | Beeston, Nottinghamshire |
| Orrell | Edge Hall Road | 3,000 | Orrell, Greater Manchester |
| Rosslyn Park | The Rock | 2,000 | Roehampton, London |
| Saracens | Bramley Road | 2,000 | Enfield, London |
| Wasps | Repton Avenue | Sudbury, London |