|Location||South of Mount Desert Island, Maine|
|Tower height||17.5 m (57 ft)|
|Tower shape||Conical Tower|
|Markings||Natural granite, black lantern|
|Heritage||National Register of Historic Places listed place|
|First lit||1847 (current tower)|
|Focal height||75 ft (23 m)|
|Lens||3rd order Fresnel Lens (original),|
|Range||20 nmi (37 km; 23 mi)|
|Characteristic||Fl W 15s|
|Fog signal||HORN: 2 every 30s operates continuously|
|USCG no.||1–5 (the first lighthouse in the Light List)|
Mount Desert Light Station
|Architect||Alexander Parris; US Army Corps of Engineers|
|MPS||Light Stations of Maine MPS|
|NRHP reference No.||88000155|
|Added to NRHP||March 14, 1988|
Mount Desert Light is a lighthouse on Mount Desert Rock, a small island about 18 nautical miles (33 km; 21 mi) south of Mount Desert Island, in the U.S. state of Maine. While the first light station was established in 1830, the current lighthouse was built in 1847. It was listed on the National Register of Historic Places as Mount Desert Light Station in 1988.
The conical granite structure was one in a series of lighthouses in Maine designed by architect Alexander Parris. A bell tower and fog bell were added in 1858, as well as a new lantern with a 3rd order Fresnel lens. The bell was replaced by a steam-powered whistle in 1889. The present keeper's house was built in 1892. The station was electrified in 1931 and automated in 1977; around that time, the lantern was removed and the lens was replaced aero-beacon. In 1985, a replica of the lantern was installed, and circa (c.) 1995, the aero-beacon was replaced with a VRB-25 lighthouse system.
The station was transferred in 1998 to the College of the Atlantic as part of the Maine Lights program. It is used as an ecology research station, primarily known for its work on finback and humpback whales.
The station is both farther offshore and more exposed than any other lighthouse on the east coast. It sustained serious damage during Hurricane Daisy (1962) and Hurricane Bill (2009). In August 2009, the boathouse was washed away, two walls of the generator building were ripped apart, and all the furniture and equipment on the first floor of the lightkeeper's house were ruined when it flooded almost to the ceiling. The college research station was subsequently closed until August 2010.