Beaver Valley is a beautiful, bucolic area that spans the Pennsylvania-Delaware border in Delaware County, PA, and New Castle County, DE. Much of this area falls within the First State National Historical Park and is adjacent to Brandywine Creek State Park, which you can walk to via scenic hiking trails. Most of these trails are open for hiking, mountain biking, horseback riding, birdwatching, and cross-country skiing. Birders often come to the area to observe numerous migratory and resident bird species. This is a fantastic, beautiful place to explore when visiting Brandywine Creek State Park or First State National Historical Park; if you hike up to Beaver Valley, you can tell people that you've walked to Pennsylvania!