Thordarson’s Rock Island Boathouse was built in 1929 by Chicago inventor and millionaire Chester Thordarson and greets visitors arriving to Rock Island on the Karfi ferry. The lower level of the boathouse is built to accommodate two 50-foot yachts. The 40 by 70-foot architectural structure atop it, with its beautiful stone and arched windows, is a historical treasure and listed on the National Register of Historic Places.
Except for the red tile roof, it was constructed using stone and building materials from the island. The boathouse is open daily during the park season or by private appointment with the park ranger. Travel to Rock Island via the Karfi Ferry from Washington Island, which runs from Memorial Day through Columbus Day.