Fort Delaware State Park is closed Saturday and Sunday due to the high temperatures.
The decision was made in the interest of safety for park staff, volunteers and patrons, because Pea Patch Island has limited air conditioning, and it can be difficult to get anyone suffering from a heat-related emergency off the island, DNREC said.
In addition, the park's Civil War re-enactors wear heavy wool costumes.
Anyone who bought a ticket to Fort Delaware for Saturday or Sunday can get either a refund or a credit for a future visit.
For more information, call Fort Delaware/For DuPont State Parks at 302. 834.7941.