Harris brand National Park Quarters Folder, 2016 through 2021, 60 Openings, Holds P & D Mint Quarters. The National Park Quarters Coin Act of 2008 - Requires quarters, beginning in 2010, to have designs on the reverse depicting one national site in each state, the District of Columbia and territory of the United States. 56 Different designs will complete the program from 2010 through 2021. Whitman Folders are built from the safest archival safe materials known. Inert and safe for all coins. 5.75" x 7.75" closed, 17.75" x 7.75" open.