Brownston House is a Grade I listed building at Devizes, Wiltshire, England, dating from the beginning of the 18th century.
Built of dark rubbed brickwork of fine quality, the house has two storeys and an attic and basement. The wide symmetrical front has a three bay central projection. There is a stone plinth, chamfered stone quoins, and an elaborate stone cornice. The central main entrance has a tall eight-panel door in a plain frame with a stone surround. The hipped roof is of old tiles, and has three dormer windows, and the house has square brick chimneys with stone quoins.
The house was built about the year 1700 for Francis Merewether of Devizes and Easterton, who was High Sheriff of Wiltshire for 1700. He was Member of Parliament for Devizes in 1701 and again from 1703 to 1705.
In 1720 the house was occupied by Thomas Browne, a barrister, who made additions in Bath stone to give the house its present form. His initials are on the heads of the rainwater pipes. He was still living there in 1736.
The house was in the possession of members of the Garth family from about 1740 to 1779. John Garth (1701–1764) was Member of Parliament for Devizes in 1740 and continued to serve until his death in 1764. He was the son of Colonel Thomas Garth by his marriage to Elizabeth Colleton, a granddaughter of Sir John Colleton, 1st Baronet, one of the proprietors of South Carolina. Garth's wife Rebecca Brompton was the granddaughter of Sir Richard Raynsford, Chief Justice of the King's Bench. Their son Thomas Garth became a general of the British Army and an Equerry to George III. Their son Charles Garth was a barrister and another Member of Parliament for Devizes. Before that, he was successively Crown Agent for South Carolina, Georgia and Maryland. On his father’s death Charles succeeded him as a Member of Parliament for Devizes for sixteen years, between 1764 and 1780, and Brownston House was his Devizes home from 1764 to about 1779. By 1780, Charles Garth had moved permanently to Walthamstow, near London.