Ha Ha Tonka State Park is a 3,751-acre public recreation area near Camdenton, Missouri, on the Niangua arm of the Lake of the Ozarks, known for both the ruins of a stone mansion and a striking Ozark karst landscape. The estate began in 1905 when Robert McClure Snyder Sr. started building a European castle-style summer home; after his death in 1906, his sons completed it in the early 1920s. The mansion later operated as a hotel before fire destroyed it in 1942, leaving the ruins preserved today. Acquired by the state in 1978, the park also features springs, caves, sinkholes, natural bridges, and trails through a designated karst natural area.