Caswell Memorial State Park preserves two hundred fifty-eight acres of rare riparian oak woodland along the Stanislaus River southwest of Ripon, protecting a habitat once widespread in the Central Valley but now threatened. Established in 1952 and opened to the public in 1958, the park took its name from landowner Thomas Caswell after his children and grandchildren donated one hundred thirty-four acres of forest to the state in the 1950s. Its importance centers on habitat conservation, especially as a refuge for endangered species such as the riparian brush rabbit, whose sharp decline reflects the broader loss of riverside forest across the region.