Ridley Creek is a small, intimate freestone stream flowing through Delaware and Chester counties in southeastern Pennsylvania. The watershed covers 38 square miles with a mainstem length of 24 miles, transitioning from a designated High Quality Trout Stocking Fishery in its upper reaches to a Warm Water Fishery in its non-tidal lower sections before meeting the Delaware River. The creek is the highest quality stream in Delaware County, with its middle watershed dominated by the 2,606-acre Ridley Creek State Park, which provides significant protected open space. The stream offers diverse angling experiences, from fly-fishing-only catch-and-release sections for trout to more casual fishing for warmwater species.