Koch, the son of one of Milwaukee’s pioneer architects, Henry C. Koch, designed this Beaux-Arts classical courthouse. He studied at the Ecole des Beaux-Arts in Paris and at MIT before becoming a partner in his father’s firm. The influence of the Ecole is apparent in the courthouse’s monumental design with a cross-shaped plan and rich ornamentation.
The three-story building occupies Lancaster’s central square, surrounded by the city’s commercial district. Three layers of brick—red, brown, and light brown—clad the exterior walls and contrast with the decorative trim of chocolate-colored Lake Superior brownstone. Fluted brownstone pilasters with a shield-like motif rise between the window bays of the second and third stories. Pediments over the first-story windows, cartouches, dentils, a modillioned cornice, and knobbed finials all contribute to the classical appearance. But the dramatic roofline makes the design especially striking. An octagonal dome of copper and glass, ringed by ocular openings near the base and surmounted by an open domed lantern with an acanthus-leaf crown, dominates the building. Inside, the dome arches over a three-story space enriched by Ionic columns, ornamental iron balustrades, and murals on the spandrels.