The hamlet of Trewen is situated 5 miles (8 km) west of Launceston. The parish church of St Michael is in the village at OS Grid Ref SX251835. The little church has a bellcote rather than a tower. "The church is an ancient granite building in the Early Perpendicular style, which was restored in 1863/1864; it comprises a chancel, nave, and north aisle". The font is Norman, square and plain. The only other hamlet in the parish of Trewen is Piper's Pool which straddles the A395 road.