The New Castle Armory was built as a Federal Public Works Project in 1938 to house Troop K, the 103rd Calvary of the Pennsylvania National Guard.
Ashler stone was used by the Thayer Company of New Castle to design this Romanesque structure, although the building as is classifed as Art Deco. Like most armories built in Pennsylvania for calvary units at the time, the building has an I-floor plan with front administrative offices and rear stables connected by a riding hall. These armories were mostly built on the outskirts of towns to provide the horses with grazing lands.
The armory is constructed in the Art Deco architectural style and is on the National Register of Historic Places.