Mount Tarn is a small mountain

Mountain

Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...

 located on the southernmost part of the Strait of Magellan

Strait of Magellan

The Strait of Magellan comprises a navigable sea route immediately south of mainland South America and north of Tierra del Fuego...

, in Brunswick Peninsula

Brunswick Peninsula

Brunswick Peninsula is a large peninsula in Magallanes y la Antártica Region, Patagonia, Chile, at . It is wide at its base in the north, and almost in the south. It measures in length from the base to Cape Froward, the southernmost point of the American mainland. This yields an area of more...

, about 70 km south of Punta Arenas, Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

. It is in the southern extreme of continental Chile very close to Cape Froward

Cape Froward

Cape Froward is the southernmost point on the mainland of South America. It is located in the North shores of Magellan Strait, being the southern tip of the Brunswick Peninsula; in Chilean territory....

, surrounded by historic places such as Fort Bulnes

Fuerte Bulnes

Fuerte Bulnes is a Chilean fort located by the Strait of Magellan, 62 km south of Punta Arenas. It was founded in 1843 over a rocky hill at Punta Santa Ana, under the command of President Manuel Bulnes Prieto....

 and Puerto del Hambre

Puerto Hambre

Puerto Hambre, originally Ciudad del Rey Don Felipe, also known as Puerto del Hambre and at one time as Port Famine, is a historic settlement site at Buena Bay on the west side of the Strait of Magellan approximately south of Punta Arenas in the Región de Magallanes y la Antártica Chilena,...

 (Port Famine).

From the summit it is possible to see the Strait of Magellan, Dawson

Dawson Island

Dawson Island is an island in the Strait of Magellan that forms part of the Tierra del Fuego archipelago, 100 km south of the city of Punta Arenas in Chile, and part of the Municipality of Punta Arenas. It is located southeast of Brunswick Peninsula and is an approximately 1290 km² tract...

 and Tierra del Fuego

Tierra del Fuego

Tierra del Fuego is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of a main island Isla Grande de Tierra del Fuego divided between Chile and Argentina with an area of , and a group of smaller islands including Cape...

 islands, and many other smaller ones; the Darwin Mountain Range, Mount Sarmiento, and most of the Brunswick Peninsula.
According to lawyer and historian, Mateo Martinic Beros in his book Cartografía Magallánica 1523-1945, the mount was named after the British surgeon

Surgeon

In medicine, a surgeon is a specialist in surgery. Surgery is a broad category of invasive medical treatment that involves the cutting of a body, whether human or animal, for a specific reason such as the removal of diseased tissue or to repair a tear or breakage...

, John Tarn , who first ascended the mountain in February, 1827 while traveling with Robert FitzRoy

Robert FitzRoy

Vice-Admiral Robert FitzRoy RN achieved lasting fame as the captain of HMS Beagle during Charles Darwin's famous voyage, and as a pioneering meteorologist who made accurate weather forecasting a reality...

 on HMS Adventure

HMS Aid (1809)

HMS Aid was a 10-gun Royal Navy transport ship launched in 1809 at Kings Lynn. She was converted to a survey ship in March 1817, and was renamed HMS Adventure in 1821. The ship was sold in 1853....

, and later, while traveling with Phillip Parker King in HMS Beagle

HMS Beagle

HMS Beagle was a Cherokee-class 10-gun brig-sloop of the Royal Navy. She was launched on 11 May 1820 from the Woolwich Dockyard on the River Thames, at a cost of £7,803. In July of that year she took part in a fleet review celebrating the coronation of King George IV of the United Kingdom in which...

), during their surveying voyage from 1826 to 1830.