Warren Woods State Park is a 311-acre (126 ha) nature preserve and public recreation area in Berrien County, Michigan, near the village of Three Oaks.

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.

[7] Many of the beeches, with their smooth, thin, silver-grey bark, are heavily scarred by hand-carved graffiti, some of it decades old; however, the practice seems to have fallen out of favor in recent years.

In the middle of the park the trail crosses the Galien River on a pedestrian bridge, where there is an interpretive station.

The park contains the 42-acre (17 ha) Warren Woods Ecological Field Station owned and operated by the University of Chicago.