Counties 1 Middlesex
| Current season or competition: 2025–26 | |
| Sport | Rugby union |
|---|---|
| Instituted | 1987 |
| Number of teams | 12 |
| Country | England |
| Holders | Hackney (1st title) (1995–96) (promoted to Herts/Middlesex 1) |
Counties 1 Middlesex (formerly Middlesex 1) is a level 7 Rugby Union league with teams from north-west London taking part. Historically, the league was a level 10 completion, and the division was cancelled at the end of the 1995–96 campaign after nine seasons due to the merger of the Hertfordshire and Middlesex regional leagues. After nearly twenty years, ahead of the 2025–26 season, the league was re-formed following the decision to have mostly Hertfordshire teams in Counties 1 Hertfordshire. Promoted teams typically move up to Regional 2 Thames and relegated sides go down to Counties 2 Middlesex.