GRG - Black Diamond is one of the Washington 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
GRG - Black Diamond is in King County, Washington. Its approximate coordinates are 47.27596, -121.99938.
Check in at GRG - Black Diamond
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.