A 311-acre state park in Berrien County, Michigan, near the town of Three Oaks. It is leased by private owners to the state of Michigan.
Named for Edward Kirk Warren (1847-1919), the inventor of the featherbone corset (which replaced the whalebone corset with turkey bones and secured his fortune). Starting in 1879, Warren bought 150 acres of the woods and 250 acres of the dunes, setting it aside for preservation.
Home to the last climax beech-maple forest in Michigan, which occupies 200 acres. The virgin North American beech (Fagus grandifolia) and sugar maple (Acer saccharum) forest has specimens 125 feet tall and with girths greater than 5 feet in diameter. The remaining area in the park consists of floodplain oak-hickory forest. Because of the size and age of the trees, and the rarity of the ecosystem, the area has been designated since 1967 as a National Natural Landmark.