Mount Desert Rock Light is located roughly 20 miles south of Mount Desert Island, near Frenchboro. The station was established in 1830. The current tower (58 feet tall, 75 foot high focal plane) was built in 1847. The original optic was a 3rd-order Fresnel, but now is VRB-25. The lighthouse flashes white every 15 seconds and the fog signal sounds 2 blasts every 30 seconds. It was automated in 1977. It is an active aid to U. S. Coast Guard navigation. The property is maintained by College of the Atlantic.

The lighthouse (1847), keeper's house (1893), boat house (1895), cistern, and storage building are still standing.