Merthyr Mawr House was constructed between 1806 and 1809 on a new site by Sir John Nicholl in a classical style, replacing the earlier 16th/17th century Hall of the Stradling family. The house is a five-bay two-storey classical mansion faced in white local carboniferous limestone, with a hipped roof and sash windows, and central single-storey porch with Tuscan columns in the north front. A lower wing, partly built later than the main projects to the east, while on the west side a veranda with a glass canted roof supported on cast-iron pillars, built in 1819, runs along the entire length of the house. The Old Hall was situated to the south-west of the 19th century house, on or near the site of the Farm; remains of the Tudor courtyard now forms one of the farm outbuildings, the rest having been demolished c 1806.

Associated with:
Park/gardens (Nprn265764).