Maesteg House was a manor house built on the south slope of Kilvey Hill, Swansea. It was built in the mid 19th century by the copper and tin industrialist Pascoe St Leger Grenfell. The building is no longer there, as it was demolished shortly after the First World War to make way for new housing development.^[1][2]

The house is described as being an irregularly shaped block 70ft wide by 60ft deep, with a hipped roof. On the front of the house there were two full-height bay windows with peaked slate roofs. A conservatory formed an extension of the eastern side.^[2]

There was a tree-lined avenue which was the entrance drive to the house.^[3]

The main lodge, with the stables, greenhouses, and Maesteg cottage, stood at what is now the junction of Morris Lane and Grenfell Park Lane. There was a second lodge near the junction of Kinley Street and Port Tennant Road.^[2]

Maesteg house was built sometime in the 1840s by Pascoe St Leger Grenfell, who had inherited copper and tin businesses in the Tawe valley from his father, also named Pascoe Grenfell. The Grenfell family originated from Cornwall, and the Pascoe Grenfell the younger spent time being educated in England and France, before moving to Swansea to take control of Pascoe Grenfell & Sons smelting business which he inherited from his father who died in 1838. It was when Grenfell the younger moved to Swansea that he had Maesteg House built, where he raised his children.^[1][4]

Maesteg House was notable for being the only house built by the Swansea industrialists that lay near the industrial workers and on the east side of the River Tawe, and thus breathing the same toxic air as their workers.^[5][6][7]

Elizabeth Mary Grenfell, who was Pascoe St Leger Grenfell's daughter, lived at the house after the death of her father. She was involved in local philanthropy, aiding the welfare and religious development of the local community. During her time Maesteg House would be sometimes used to help the community. Once a year the railway-men of the district were invited to the House where a large tent was erected on the grounds.^[8]

Grenfell's niece Katherine was the last of the Grenfells to live at Maesteg House. She used the house to run a school for local children.^[1][4]

During the First World War the house was used to house at least eighty Belgian refugees. By this point the house had been uninhabited for some time and was in poor condition. To be able to house the refugees properly the house underwent repairs and maintenance over a period two years and at a cost of £500^[9] (About £41,000 in 2023 value).

Soon after the war in about 1920 the house was demolished and the land of the house was used to build Grenfell Park housing estate, an extension of the St Thomas suburb which had already been built immediately in front of the house.^[2][1]

The house was built on the southern slope of Kilvey Hill, it was facing southwards overlooking Fabian Bay. There are no traces left of the house but Grenfell Park Road follows the line of the drive of the house, with the house itself standing roughly where the junction of Grenfell Park Road and St Leger Crescent is.^[2]