Seward's Day was officially observed in Alaska on Monday, but today, March 30, is the date in 1867 on which the reason for the state holiday occurred.
On that date, the U.S. and Russia signed a treaty (in English and French) that officially transferred ownership of The Great Land from the Tsars to the Feds for a purchase price of $7.2 million.
The purchase was ridiculed in the U.S. as "Seward's Folly," "Seward's Icebox" and the seldom-heard epithet "Polar Bear Garden."
Because of disputes in Congress over approving the money, the deal wasn't completely finished, however, until Russia cashed a check from the U.S. Treasury into gold at Riggs Bank in Washington D.C. on Aug. 1, 1868.
Joke's on all the naysayers, though. Gold was discovered in Alaska in 1896, bringing a population boom, and over the next roughly 70 years, explorers found exploitable crude oil deposits ranging from modest to massive.
Politico notes the purchase anniversary this year, and recalls the more than year-long delay over funding the purchase after the treaty had been ratified. The Congressional Globe shows the U.S. House hashing out an amendment in 1868 that would prevent any such purchase treaties being made before funding is secure.
Take a trip through the Library of Congress's Alaska Purchase research portal, here. See an image of the very check that Russia cashed, here. And read an 1877 magazine article, here, from Harper's Monthly about Alaska's first 10 years as a territory.
And if you're looking for a cocktail to toast the sale, try an "Alaska Cocktail," a martini variation whose origins are unknown but which first appeared in the classic 1930 Savoy Cocktail Book.