Hessian Barracks, formerly known as Frederick Barracks, is an historic barracks building located in Frederick, Maryland. The State of Maryland contracted to build a barracks in the summer of 1777, but it was not completed until 1781. There were two L-shaped buildings built on the site, but one was demolished in 1871. The building is a two-story stone structure with gallery porches and a gable roof. Hessian Barracks was listed on the National Register of Historic Places in 1971.