The Anacostia Tributary Trail System is a unified and signed system of stream valley trails joining trails along the Anacostia tributaries of Northwest Branch, Northeast Branch, Indian Creek and Paint Branch with a trail along the Anacostia River, set aside and maintained by the Maryland-National Capital Park and Planning Commission in the Maryland suburbs of Washington, D.C. ATTS is a part of the East Coast Greenway, a 3,000-mile-long system of trails connecting Maine to Florida and the American Discovery Trail, a trail system stretching from the Delaware coast to San Francisco. Wikipedia