Armory of the First Corps of Cadets

The Armory of the First Corps of Cadets is an historic armory at 97-105 Arlington Street and 130 Columbus Avenue in Boston, Massachusetts. The four-story granite structure was designed by William Gibbons Preston and built beginning in 1891 and finished in 1897. Due to political unrest during the period, the building was designed to withstand mob violence. Its most prominent feature is its six-story tower. It is built in the Romanesque Revival style. The buildings staircases are built by the Guastavino system, as are some tower vaults.

The building was listed on the National Register of Historic Places in 1973 and designated as a Boston Landmark by the Boston Landmarks Commission in 1977. It was known as the Park Plaza Castle and owned by the adjacent Boston Park Plaza Hotel & Towers, which used it as a banquet facility up until 2014. Currently managed by another company, the venue space is now referred to as the "Castle at Park Plaza."