White Clay Creek State Park near Newark, Delaware, preserves 3,559 acres along White Clay Creek beside Pennsylvania’s White Clay Creek Preserve. Its creation grew from a post-World War II struggle over plans to dam the creek and flood the valley for a reservoir. Opposition by local residents and conservation groups helped defeat the project, while state action, DuPont land donations, and later acquisitions gradually assembled protected land on both sides of the state line. Renamed in 1995, the park now offers extensive trails, a nature center, historic structures, and important Mason-Dixon survey sites, while safeguarding a creek valley later recognized in the National Wild and Scenic Rivers System.