The Lyon County Courthouse is located in Rock Rapids, Iowa, United States.

In 1873 Rock Rapids was chosen as the county seat because of its central location, and the first courthouse was erected in 1875.

[4] A lion couchant is located above the main entrance, and is a play on the county's name Lyon.

[2] The central rotunda on the interior features an art glass skylight dome and the county seal in a mosaic of ceramic tile on the floor.

They are possibly the work of William Peaco, who has similar murals in the Greene County Courthouse in Jefferson.