According to a friend,of whom is a US Marshall,The National Parks are controlled by The Dept. of The Interior.The Dept.of The Interior is Completely a Federal Jurisdiction,However...Any Law enforcement officer, of that state,Can Hold you in custody for 72hrs.& Confiscate any weapons,Should they deem it Necessary,As per their own Better Judgement.Even if you are found to be "Legitimate"Afterward,Getting your gun back can or Will be,A whole different case! Sounds Like a "Grand-Mal PITA" to go through,However it's Peanuts,Should the act of Defending You or your Family,Have to be carried out!Are you an NRA Member?The NRA will be your BEST Defense,should you need it!I am NOT Advocating Breaking the Law,by ANY means! I do Have Affiliation with The NRA,I am A Member!