If you have a Maine loon license plate, some state parks and historic sites around the state are allowing you free admission Sunday.  There is no rain date and according to WABI, there are some exceptions.

According to the Maine.gov website, there is a list of exceptions:

Acadia National Park, Allagash Wilderness Waterway (AWW), Baxter State Park, the Maine Wildlife Park (IF&W), Peacock Beach, Scarborough Beach, Swan Island (IF&W), Penobscot River Corridor (PRC) or the Penobscot Narrows Observatory in Prospect, though admission to Fort Knox State Historic Site, right next door, will be free that day.

Check out the list of cool stuff going on in the great state of Maine with the calendar of events with the Bureau of Parks and Lands.