The Alaska Purchase (Russian: Продажа Аляски, tr. Prodazha Alyaski) 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 State William 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.
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 a state in 1959.
Russia was in a difficult financial position and feared losing Russian America without compensation in some future conflict, especially to the British, with whom they had fought in the Crimean War (1853–1856). While Alaska attracted little interest at the time, the population of nearby British Columbia started to increase rapidly a few years after hostilities ended, with a large gold rush there prompting the creation of a British crown colony on the mainland in addition to the one that was already established on Vancouver Island, where the French and British fleets had retreated after the Battle of Petropavlovsk in the Russian Far East.