The Hudson and Boston was originally chartered in 1828 as the Hudson and Berkshire Railroad by James Mellen in order to build a railroad line from Hudson, New York to the Massachusetts state line. Construction began in 1835 and was completed in 1838. The company was leased to the Berkshire Railroad, along with the connecting West Stockbridge Railroad, in 1844, but was sold at foreclosure to the Western Railroad of Massachusetts on November 21, 1854. The name was changed to the Hudson and Boston Railroad on February 23, 1855, and the part east of Chatham was abandoned around 1860, since it was redundant with the newer Albany and West Stockbridge Railroad (part of the Boston and Albany Railroad main line).
The line was acquired by the B&A on November 2, 1870, and thus became their Hudson Branch, also called the "Hudson and Chatham Branch."