If you have a state park sticker on your vehicle, there is no charge. I have been asked to warn riders that there is a heavy deer fly infestation from the middle of June to the middle of August. It varies from day to day and from one area to another, but for most of those two months you will need to protect yourselves and use ear coverings for your horse. It wouldn't hurt to carry a net to cover your head and neck. Each site has posts to picket your horse, and there are two sets of vault toilets.
Water is available from hand pumps.
It took 17 pumps before the water started to flow and an additional 37 pumps to fill a two and half gallon pail. Waterloo is the largest State Park in Michigan with almost 20,000 acres. Horses are not allowed in the entire area, but you will find 25 miles of trails that are color coded. The major trails are marked, but there were many other trails that didn't seem to have any markings whatsoever. We started on the Blue Trail and branched off on an unmarked trail.