Sumner Strait is a strait

Strait

A strait or straits is a narrow, typically navigable channel of water that connects two larger, navigable bodies of water. It most commonly refers to a channel of water that lies between two land masses, but it may also refer to a navigable channel through a body of water that is otherwise not...

 in the Alexander Archipelago

Alexander Archipelago

The Alexander Archipelago is a long archipelago, or group of islands, of North America off the southeastern coast of Alaska. It contains about 1,100 islands, which are the tops of the submerged coastal mountains that rise steeply from the Pacific Ocean. Deep channels and fjords separate the...

 in the southeastern region

Alaska Panhandle

Southeast Alaska, sometimes referred to as the Alaska Panhandle, is the southeastern portion of the U.S. state of Alaska, which lies west of the northern half of the Canadian province of British Columbia. The majority of Southeast Alaska's area is part of the Tongass National Forest, the United...

 of the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

. It is about 80 miles (128.7 km) long and 10 miles (16.1 km) wide, extending from the mouth of the Stikine River

Stikine River

The Stikine River is a river, historically also the Stickeen River, approximately 610 km long, in northwestern British Columbia in Canada and southeastern Alaska in the United States...

 to Iphigenia Bay on the Gulf of Alaska

Gulf of Alaska

The Gulf of Alaska is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the east, where Glacier Bay and the Inside Passage are found.The entire shoreline of the Gulf is...

, separating Mitkof Island

Mitkof Island

Mitkof Island is an island in the Alexander Archipelago in southeast Alaska, at . between Kupreanof Island to the west and the Alaska mainland to the east. It is about wide and long with a land area of , making it the 30th largest island in the United States.The island is relatively flat with...

, Kupreanof Island

Kupreanof Island

Kupreanof Island is an island in the Alexander Archipelago in southeastern Alaska. The island is long and wide with a total land area is , making it the 13th largest island in the United States and the 170th largest island in the world. The Lindenberg Peninsula, on the southeast side of the...

, and Kuiu Island

Kuiu Island

Kuiu Island is an island in the Alexander Archipelago in southeastern Alaska. It lies between Kupreanof Island, to its east, and Baranof Island, to its west. The island is long, and 10–23 km wide. It is nearly cut in two by Affleck Canal. It has of land area, making it the 15th largest...

 on the north from Zarembo Island

Zarembo Island

Zarembo Island is an island in the Alexander Archipelago of southeastern Alaska, United States. It lies directly south of Mitkof Island and northwest of Etolin Island. To the northwest is Kupreanof Island and to the southwest is Prince of Wales Island. It has a land area of 183.14 sq mi , making it...

 and Prince of Wales Island on the south.

The fur trader William Brown was the first Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

an to visit the strait about 1793. Later the same year James Johnstone

James Johnstone (explorer)

James Johnstone was a British naval officer and explorer. He is noted for having served as sailing master of the armed tender HMS Chatham and later acting lieutenant during George Vancouver’s 1791-95 expedition to the Pacific Northwest...

, one of George Vancouver

George Vancouver

Captain George Vancouver RN was an English officer of the British Royal Navy, best known for his 1791-95 expedition, which explored and charted North America's northwestern Pacific Coast regions, including the coasts of contemporary Alaska, British Columbia, Washington and Oregon...

's officers during his 1791-95 expedition

Vancouver Expedition

The Vancouver Expedition was a four-and-a-half-year voyage of exploration and diplomacy, commanded by Captain George Vancouver. The expedition circumnavigated the globe, touched five continents and changed the course of history for the indigenous nations and several European empires and their...

, charted it. It was named in 1875 by W. H. Dall

W. H. Dall

William Healey Dall was an American naturalist, a prominent malacologist, and one of the earliest scientific explorers of interior Alaska...

 in honor of Charles Sumner

Charles Sumner

Charles Sumner was an American politician and senator from Massachusetts. An academic lawyer and a powerful orator, Sumner was the leader of the antislavery forces in Massachusetts and a leader of the Radical Republicans in the United States Senate during the American Civil War and Reconstruction,...

.

The Cape Decision Light

Cape Decision Light

Cape Decision is a lighthouse located on Kuiu Island adjacent to Sumner Strait in Southeast Alaska.-History:The first attempt to light these waters was an acetylene lantern placed on the Spanish Islands, just off the southern end of Kuiu Island...

is a notable aid-to-navigation on Sumner Strait.