NPS property became legal a few years ago. I sponsored a 2nd amendment rally at the Jefferson National Expansion Memorial the week it became legal (We had to CCW though because of the City of St. Louis). No problems on the arch grounds. The NPS p[olice who were there to greet us knew the laws, knew we were nostly armed, no problems! If I can locate the photo from home I'l post it. I went to Arch grounds that foggy cold morning and stood there with a sign with date.