The Isle au Haut Thoroughfare, immediately off the Isle au Haut coast, is a navigational passage between Isle au Haut and Kimball Island. Isle au Haut is located on the outskirts of Penobscot Bay, about six miles southeast of Stonington and 25 miles east of Rockland. The waterway provides access to home port for a small local fishing fleet and seasonal recreational craft, and affords protected passage for small vessels.
The project is a 1,200-foot-long channel, six feet deep and 75 feet wide, constructed through the shoal at the eastern end of the thoroughfare. It was completed in 1958.