This comprehensive guide is the first to tell where to find 123 Passport To Your National Parks® cancellation stamps at more than 50 National Park System sites in Washington, D.C. and the surrounding area. Included are the exact locations of each stamp¿many of which are hard to find¿with detailed directions and stamping tips, as well as interpretive information to help you enjoy each national park visit.Look inside to find:¿ The location of every cancellation in Washington, D.C. and the surrounding areä Where to find unique and duplicate cancellations¿ Hours of operation and ¿don¿t miss¿ highlights at each national park, memorial, and historic site