Lovebirds Donuts in Kittery, Maine has gluten-free donuts! The entire place is vegan, by the way, down to the coffee creamer, but you won’t know the difference. They make their gluten-free donuts completely separately, using a dedicated fryer, and are a total celiac favorite of locals and travelers alike. Not a dedicated gluten-free facility, but super careful.
450 U.S. Route 1, Kittery, ME, USA