Hamilton Marsh State Park is one of the New Jersey parks in thicket's catalog. thicket is a field guide to the parks near you: it maps the ones you have never noticed, gives you a reason to actually go, and keeps a record of where you have been.
Where it is
Hamilton Marsh State Park is in Mercer County, New Jersey. Its approximate coordinates are 40.16340, -74.70297.
Check in at Hamilton Marsh State Park
thicket verifies you are actually here by GPS when you check in, so a visit means you went. Checking in builds a streak, earns achievements, and fills in your map of the places you have been.