Lancaster's eye-catching Prairie School Municipal Building was constructed in an era of civic pride to serve the governmental and entertainment needs of the community. Built to replace an earlier, demolished city hall, the total cost of this building, its equipment and site was reported to be $130,000. The building included city offices, meeting rooms and the fire department, in addition to the 800 seat Grantville Theater. The dual nature of the building is expressed on the exterior; two-story, terra cotta trimmed pilasters mark the office block, while a bold white terra cotta border frames the theater wing.

The Municipal Building is a prized work of the Madison Prairie School architectural firm of Claude and Starck. Here, the style is characterized by the facades' strong geometric organization, the horizontal emphasis, the grouped windows, and the applied terra cotta ornamentation. The firm's original design called for cream brick and a higher degree of terra cotta ornamentation. The final design was carried out in amber "Ohio matte brick," with a reduction in the number and a simplification of the terra cotta framing panels on the office block that was probably the result of budgetary concerns.

The interior retains many of its original features. The office portion is finished with plaster and oak moldings. The upstairs meeting room has a brick fireplace at one end. The theater retains its plaster-finished lobby and the ornamental plasterwork in the auditorium. The auditorium's decoration is classically inspired and includes swags, garlands and classical friezes and borders.

The Lancaster Municipal Building is publicly owned, and is open during regular business hours. The Grantville Theater is open for regular theatrical showings.