Herts/Middlesex 1 is a tier 9 English Rugby Union league. It is organised by the London and South East Division Rugby Football Union and is the top tier competition for clubs in Hertfordshire and parts of north-west London that traditionally was encompassed by the historic county of Middlesex. When it was formed ahead of the 1992–93 season it was known as Herts/Middlesex, changing to its current name by the 1996–97 season.