Cromwell Island is as enchanting as the crystal-clear waters of Flathead Lake. It offers a view of the famous Wild Horse Island, where the Salish and Kootenai tribes used to swim their horses to shield them from other tribes. During the 1930s, a dam was constructed near Polson, Montana, at the exit of the Flathead River. Before the dam’s completion, Cromwell Island sometimes connected to the mainland during low water periods, making it a practical place for Native Americans to drive their horses onto the land before swimming them to Wild Horse. Today, Cromwell Island is once again a complete island, and it is currently up for sale.
With nearly 200 square miles of surface area and 185 miles of shoreline, Flathead Lake is the largest natural freshwater lake in the region west of the Mississippi River — even surpassing Lake Tahoe! Cromwell Island, with its approximately 348 acres and nearly three miles of shoreline, is believed to be the largest privately-owned freshwater island in this area, held under a single ownership. Like Loch Ness, Flathead Lake is said to have its own monster. The Kootenai Tribe’s oral history includes tales of a huge antlered creature in the lake, with documented sightings dating back to 1889, when a steamboat captain and 100 passengers reported a “whale-like” object diving after being shot at by a passenger. Locals have affectionately named this creature “Flessie,” a nod to her Scottish counterpart.
In the late 1980s, Robert M. Lee, a distinguished collector of cars and antique firearms, as well as a noted explorer and conservationist, acquired Cromwell Island. Before his passing in 2016, Lee and his wife, Anne, began building an extensive structure with over 45,000 square feet intended as their permanent residence. Even in its incomplete state, the structure possesses a grand presence reminiscent of Versailles. The captivating allure of Cromwell Island persists as it is now on the market, offering the next owner a chance to shape the future of this historic location.