Don't know of any special paperwork required but some parks do have an entry fee. You can get passes on line at the Bational park web sites. Some passes are free if you are disabled or have other qualifying needs.
If over 62, be sure to get the Senior Pass. Free entry to National Parks for life, 50% off camping at most. $10 one time fee, as I remember. Great deal!!
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JLeising
2012 Solera "S"
Calif SF Bay Area
Can anyone advise if any special paperwork needed to enter federal parks prior to entering?
If you're over 62, get a Senior Pass. Can usually purchase at the park you're entering. Good for life and most fees at Fed parks are either waived or discounted.