Passport cancellation stamps are a fun and free way to remember all of your visits to national parks. Collect your stamps in a special book (sold at cooperating bookstores) or on park brochures, Junior Ranger books, or blank paper.
The George Washington Memorial Parkway is a passport stamp collector's treasure trove. All 32 parkway-related stamps are available at parkway headquarters on weekdays from 8 am to 4:15 pm. A selection of these stamps is also available at Arlington House, the Arlington National Cemetery Visitor Center, Clara Barton National Historic Site, Glen Echo Park, and Great Falls Park.