The Duchy League was an English football competition based in the eastern half of Cornwall, but also included a few sides from over the border in Devon. The League was formed in 1965 as a merger of the Liskeard & District League and the St. Austell & District League. It had three divisions headed by the Duchy League Premier Division, which operated at level 13 of the English football league system. It was a feeder to the East Cornwall League. In 2014–15, Padstow United won the Premier Division, and earned promotion to the East Cornwall League.

For the 2015–16 season, the Duchy League ran three cup competitions: the KMD Developments Cup; Bodmin Sports Trophies Duchy League Cup and the TJ International Reserve Team Cup. The KMD Developments Cup had the top 32 teams from the previous seasons league positions take part in a knockout cup competition, with the semi-finals and final played on neutral grounds. The Bodmin Sports Trophies Duchy League Cup featured the rest of the teams competing in a similar knockout competition, whilst the TJ International Reserve Team Cup was a competition for clubs who have a second team in the Duchy Leagues. In 2014–15, St. Stephen of the Premier Division won the KMD Developments Cup; Veryan won the Bodmin Sports Trophies Duchy League Cup (as well as winning Division Three) and the Reserve Cup was won by Grampound Reserves.

Following the 2022–23 season, the league was absorbed into the St Piran League.

* Club resigned from the league during the season.

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