Counties 3 Herts/Middlesex

Counties 3 Hertfordshire (formerly Counties 3 Herts/Middlesex and before that Herts/Middlesex 1) is a tier 9 English Rugby Union league. It is organised by the London and South East Division Rugby Football Union for clubs in Hertfordshire and parts of north-west London that traditionally was encompassed by the historic county of Middlesex. Promotion is to Counties 2 Hertfordshire relegation is to the Hertfordshire RFU merit leagues.

Historically the league was a level 8 league but following the RFU's Adult Competition Review, from season 2022-23 it became a level 9 competition and adopted the name Counties 3 Herts/Middlesex, however ahead of the 2025-26 season a decision was taken to split out Herfordshire RFU and Middlesex RFU clubs.