Historically the Town Hall and Opera House/ Allerton Library, now the Monticello Community Building, constructed in 1896-97 in Romanesque Revival style. The main entrance is housed in a two and one-half story gable pavilion. A stone voussoir round arch frames the deeply recessed entrances. Incised in the arch is "Town 1896 Hall" and just above on the brick level, a stone panel reads "Allerton Library." In the two story tower the first story windows have short stone lintels separating tall transoms, which are topped with large stone lintels. The second story windows have average sized stone lintels and the windows on both stories have continuous stone sills. The south elevation is dominated by a large two and one-half story gable pavilion which contains bands of four windows on the lower two stories, and paired round arched vents in the upper story. The vents are especially detailed with four rowlock corbelled round arches above each and a stone lug sill. Two bays are between the tower and the gable pavilion with the first story having a recessed entrance within a flat roof porch. The continuous stone lug sill from the first story tower windows continues across the entrance porch, interrupted for the entrance. A six rowlock round arch frames the recess.