Here in NoVA we have the George Washington Memorial Parkway. It's basically a highway that links up a bunch of parks, but it can be used to get to various other destinations. Technically the George Washington Parkway is part of the National Parks Service. So, even though the parkway is entirely within the state of VA and I have a CHL, I can't carry concealed if I want to take that road to get anywhere. Haven't heard of anybody getting pinched for it yet, but I definitely wouldn't put it past the govt to prosecute anybody they catch, over what should be a total non-issue. Fortunately I don't need to take that road very often.