Boston Spa is a village and civil parish in the City of Leeds metropolitan borough in West Yorkshire, England. Located south of its post town Wetherby, Boston Spa is on the banks of the River Wharfe. According to the 2001 census the parish had a population of 4,006.
In 1744, John Shires established Boston as a spa town when he discovered magnesian, limestone and sulphur springs. In those days it was known as Thorp Spa. It declined when Harrogate became very popular as a spa town.
In 1753, a turnpike was built on the Tadcaster to Otley road, which runs through Boston Spa. In the same year, Joseph Taite built a house for the accommodation of visitors in Boston Spa that became the Royal Hotel, which is still standing, but converted into flats and shops. By 1819, Boston Spa had a population of over 600, and several inns and other houses offering accommodation. Spa baths were built to allow visitors to take the waters. On the east bank of the river lies the village of Thorp Arch, which predates Boston Spa by several centuries.
Thorp Arch hosted a World War II Royal Ordnance Factory, ROF Thorp Arch, an ammunition Filling Factory. ROF Thorp Arch closed in 1957. Part of the site is the home of the Northern Reading Room, Northern Listening Service and Document Supply Collection of the British Library. The remainder of the site is occupied by Thorp Arch Trading Estate and two prisons, now combined as Wealstun Prison.
The Boston Spa and Thorp Arch Conservation Area was designated in 1969 and extended across both Boston Spa and Thorp Arch parishes. It was revised in 2009, restricting the boundaries to Boston Spa parish and reshaped to exclude Areas of late-20th-century estate housing to the south of the High Street as they are of insufficient historic significance to merit inclusion and had not been built at the time of designation in 1969. The current conservation area boundary focuses more closely on the historic settlement. The conservation area was also extended to the west to encompass West End, an area of dwellings constructed during World War II to house workers from the nearby Thorp Arch munitions factory. The War had a major effect on Boston Spa's population, society and surroundings, and these buildings stand as a testament to that history.
When Boston Spa was founded in 1744 it was in the township of Clifford in the old parish of Bramham, in the upper division of the wapentake of Barkston Ash, in the West Riding of Yorkshire. From 1866 to 1896 it was part of the civil parish of Clifton with Boston, and became a separate civil parish in 1896. The parish was in Wetherby Rural District in the West Riding of Yorkshire until 1974, when it was transferred to the City of Leeds in the new county of West Yorkshire.