It was listed on the National Register of Historic Places in 1981 as a part of the County Courthouses in Iowa Thematic Resource.

After two votes Boonesboro retained the county seat and a three-story brick courthouse was completed in 1868 for $35,000.

It featured prominent porticos with full-height columns and a central tower capped with a dome that rose 68 feet (21 m) above the ground.

Meanwhile, the town of Montana continued to grow and expand and changed its name to Boone and incorporated what had been Boonesboro in 1892.

It features marble walls, terrazzo floors, coffered ceilings, and stained glass skylights.