Trostrey (Welsh: Trostre) is a small hamlet and parish in Monmouthshire, in southeast Wales located about 2+1⁄2 miles (4.0 km) north/northwest of Usk.

Excavations at the castle in 2000 found evidence of burial cairns from the Neolithic and Bronze Age periods.

[1] An 11th-century earthen motte-and-bailey castle was replaced in the 13th century by a small stone fort.

[2] A manor house, Trostrey Court stands 1⁄2 mile (0.80 km) east of the village.

[2] The Church of St David is dedicated to St David.