By and large these are still places people can go. You will have to make arrangements with the park rangers. The Delaware State parks now close at 10 PM unless you are camping.
In the summer 10 PM is when darkness is complete so if you want to look at bright planets or the Moon you are SOL in Delaware.
There are three dark sky sites of varying degrees of darkness to choose from. The best way to organize an outing to start planning using our Groups.io Group.
Trap Pond State Park in Sussex County, Delware: This is the darkest site with a Sky Quality Meter (SQM) reading of between 20.87 and 21.00 and dark for the Delmarva Peninsula. Spruce Knob in West Virginia and Cherry Springs have slightly darker skies but you have to travel 300 miles (three hours) to get there.
Trap Pond State Park is used primarily for our Stargaze star party in the Spring and for our informal monthly star parties. There is electricity on the field in the north west corner through GFI outlets.
Tucahoe State Park in Maryland was the primary star party site until the bright lights from Annapolis and DC wiped out the west sky. The SQM readings have hovered around 20.85 although sky glow from the large cites to the west limits viewing. It is better than observing in the city and still a favorite. We use the ballpark area.
Blackbird Forest is a group of disconnected forests where we use a hunting parking lot for observing. It is convenient to those living in Smyra, Dover, and the western lands of Delaware and eastern Maryland.
Weather terms you might find useful in a forecast before you go out.