Mansion House, Cardiff, orginally named 'Grove House', was built c.1896 for James Howell (1835-1909), founder of Howell's department stores. It was designed with a paired entrance in case circumstances should have required it being divided into 2 properties. The house remained uninhabited after Howell's death until it was sold to Cardiff City Council in 1912 for the official residence of the Lord Mayor.

It is a free classical style house of 3 bays and 2 storeys with attics and basement. Walls are rock-faced Pennant sandstone with lighter Bath stone dressings. There is a hipped slate roof on bracketed eaves. The symmetrical front has a central double entrance bay. There is an upper-storey balcony with stone balustrade and open quatrefoil ironwork. The attic has 3 full dormers with round-headed lights, and pediments.

Reference: Cadw listed buildings database.
RCAHMW, 2009.