The courthouse was designed by Fallis, a Toledo architect who had apprenticed with Charles C. Miller, had traveled in Europe, and had developed a reputation for his courthouse plans. This two-story smooth-faced limestone building has a pedimented central three-bay loggia, a modillioned cornice, and an elaborate, mansard-roofed corner tower. It stands on the foundation of the previous courthouse built in 1836–1837 and destroyed by fire in 1879. Two undistinguished additions were constructed to the south and west in 1952 and 1966. An atrium connects the old building to a glossy tan-with-red-trim south addition by TMP Associates. The modern red brick Monroe City Hall (1977, Rossetti Associates) at 120 E. 1st Street meets the courthouse on the bias.