Warren Armory is a historic National Guard armory located at Warren, Warren County, Pennsylvania. It was built in 1909, and is a 2 1/2-story, brick building with a gambrel roof in the Romanesque style. The drill hall is located on the second floor. It has a projecting central entrance bay, stone sills and lintels, brick turrets, and a crenelated parapet.It was added to the National Register of Historic Places in 1991.