The “America the Beautiful” quarters

Just for fun (click to zoom), a map of 49 of the 56 U.S. National Parks, National Forests, and National Wildlife Refuges shown on the “America the Beautiful” quarters. How many have you visited?

Locations auto-extracted from Wikipedia pages using R, and colours indicating elevation, using an elevation dataset from (a dataset which treats the Great Lakes as land) and a palette I knocked together.