
The original facade had a round-arch entrance, executed in polychrome brick, which was concealed in 1882 when a small, brick vestibule was added. The side facades each had six round-head windows on the upper story and six segmental-arch-head windows on the lower story which have been filed in with brick. The 1896 extension is clad in grey asbestos shingle. The stage housing at the end of the auditorium was extended upward and outward in 1896, increasing the fly gallery and stage depth. The cornice is adorned with a corbel table. (Two adjacent commercial buildings that now house theater functions are not included in the historic designation.) The roof is gabled with a low pitch. The Adrian Union Hall/Croswell Opera House, completed about 1866, is a two-story, rectangular structure constructed of red brick laid in common bond.
