In 1870-72, John Marius Wilson's Imperial Gazetteer of England and Wales described Boston Spa like this:
BOSTON-SPA, a village and a chapelry in Bramham parish, W. R. Yorkshire. The village stands on the river Wharfe, ¼ of a mile SW of Thorpe-Arch r. station, and 3½ NW by W of Tadcaster; and has a post office‡ under Tadcaster. It consists of a single well-built street; and has a fine bridge over the Wharfe, three hotels, a good church with a tower, built in 1814, and a Wesleyan chapel. ...
A saline spring here was brought into notice in 1744; has been recommended by distinguished physicians; and draws invalids and other visitors to the village as a watering-place. A pump-room, hot and cold baths, and other kindred appliances are in operation; and a number of handsome residences are in the neighbourhood.The chapelry includes the village, and was constituted in 1852. Rated property, £5,040. Pop., 1,123. Houses, 251. The property is subdivided. The living is a vicarage in the diocese of York. Value, £180.* Patron, Christ Church, Oxford.
GB Historical GIS / University of Portsmouth, History of Boston Spa, in Leeds and West Riding | Map and description, A Vision of Britain through Time.
Date accessed: 26th April 2017
Click here for more detailed advice on finding places within A Vision of Britain through Time , and maybe some references to other places called " Boston Spa ".