Mills Woods Mound, also called the Hudson Park Mound, is a Native American effigy mound in Madison, Wisconsin, and a rare survivor of a much larger mound landscape. Part of the former Mills Woods Mound Group of about thirty earthworks, it was built during the Late Woodland period, about 800 to 1100 A.D., by Mound Builder people for burial and ceremonial use. The animal-shaped mound, distinguished by a long tail though its exact form is uncertain, is the only one left after later construction destroyed the rest of the group. Its survival gives it notable archaeological value in a region where few effigy mounds remain.