Bigelow Cemetery State Nature Preserve is Ohio's smallest State Nature Preserve at half an acre and one of its most unusual because it is both a historical prairie and a burial ground. This prairie is a tiny remnant of the Darby Plains, a flat prairie-dominated area that once covered about 385 square miles between the Big and Little Darby Creeks. Once one of five prairie grassland regions in Ohio, the Darby Plains has disappeared except for small remnants, while most of the rest of the state was forested. The preserve contains tallgrass prairie where grasses and wildflowers dominate and trees are few, including big bluestem, Indian grass, and little bluestem, with scattered bur oak trees. Historically, woody growth was suppressed by very wet or dry soils, animal grazing, and wildfires often set by American Indians to clear routes and improve hunting, but today prairies require active management to remain open habitats. Royal catchfly, a threatened plant in Ohio, grows here in the state's best population, along with black-eyed Susan, prairie dock, and wild bergamot. Early records indicate that most of the European settlers buried here belonged to a colony largely from Vermont and Pennsylvania, with some of the earliest known tombstones dating to December 1814 and the last known burial occurring in 1892.