Great Marsh Institute is one of the Pennsylvania 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
Great Marsh Institute is in Chester County, Pennsylvania. Its approximate coordinates are 40.12550, -75.76980.
Check in at Great Marsh Institute
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.