Hey, I'm thinking one of the recent categories just changed its name. If I'm not mistaken "State Park Passport Locations" was originally "Non-NPS Passport Locations". Something like that. Anyway, I've got a related question: some of the lighthouses on the west coast have a passport-type stamp program. Since the lighthouse group is national, would that fit into this category? I am, as always, curious.
More info on the program can be found here:
http://lighthouse-society.org/passports.php