The Miami County Courthouse, completed in 1898, anchors the south side of Park Square. It is a fine example of Romanesque Revival, with rough-cut limestone walls, rounded arches over the windows, and a tall central tower carrying a four-faced clock. The architect was George P. Washburn of Ottawa, Kansas, who designed a string of similar Kansas county courthouses in the 1890s; this is among the best preserved.
The interior, open during business hours on weekdays, has a marble entrance hall and a sweeping double staircase up to a balcony around the second-floor court. The original wood-panelled main courtroom is still in use and worth a quick look. The building is on the National Register of Historic Places and was restored in 2018 — the limestone scrubbed clean, the clock mechanism rebuilt, the stained glass repaired.