Triermain is a farm in Cumbria, close to the county border with Northumberland. It is located off the Military Road (B6318), about 2½ miles west of Gilsland. In the medieval period, there was a substantive castle with a moat here, which was the baronial home of the Vaux family. A chapel at Tryermaine was documented in 12th century. The remains of Triermain Castle are situated immeiately west of the farmhouse and are a Scheduled Monument.