Trowbridge is a district, community and coterminous electoral ward on the eastern edge of the city of Cardiff, capital of Wales. The community and electoral ward includes some or all of the areas of the St Mellons estate and Trowbridge, as well as part of the Wentlooge Levels between the mainline railway and the coast. It is bounded by the village of Old St Mellons to the north; Marshfield to the east; and Splott and Rumney to the west.