The Alaska Purchase was the United States' acquisition of Alaska from the Russian Empire on March 30, 1867, by a treaty ratified by the United States Senate, and signed by president Andrew Johnson.
Russia wanted to sell its Alaskan territory, fearing that it might be seized if war broke out with the United Kingdom. Russia's primary activities in the territory had been fur trade and missionary work among the Native Alaskans. The land added 586,412 square miles (1,518,800 km2) of new territory to the United States.
Reactions to the purchase in the United States were mostly positive; some opponents called it "Seward's Folly" (after Secretary of StateWilliam H. Seward), while many others praised the move for weakening both the UK and Russia as rivals to American commercial expansion in the Pacific region. The purchase threatened British control of its Pacific coast colony, giving added impetus to Canadian Confederation, which was realized just three months later, in July 1867. The Dominion of Canada would welcome British Columbia to confederation in 1871, ending US hopes of annexation and an uninterrupted connection of Alaska to the United States.
Originally organized as the Department of Alaska, the area was renamed the District of Alaska and the Alaska Territory before becoming the modern state of Alaska upon being admitted to the Union as the 49th state in 1959.