Most Michigan parks also require an entrance/admission pass. Here's the breakdown:
$11 - Michigan registered vehicles
$5 - Michigan registered motorcycles
$31 - Non-Michigan annual pass
$9 - Non-Michigan daily pass
But 100% disabled vets, with papers, can get a year pass free. So I'm told. Planning a trip there, but haven't experienced it yet.
One Ohio SP said 100% camps free, another said no. Same for Kentucky.
If you know of a site or spreadsheet available that list all states offering discounts for vets, please post it.