Alaska Day

Alaska Day is a legal holiday in the U.S. state of Alaska, observed on October 18. It is the anniversary of the formal transfer of the Territory of Alaska from Russia to the United States which occurred on Friday, October 18, 1867.

Background
On March 30, 1867 the United States purchased Alaska from Russia for the sum of $7.2 million. It was not until October of that year that the Commissioners arrived in Sitka and the formal transfer was arranged. The formal flag-raising took place at Fort Sitka on October 18, 1867. The original ceremony included 250 uniformed U.S. soldiers, who marched to the Governor's house at 'Castle Hill'. Here the Russian troops lowered the Russian flag and the U.S. flag was raised.
The official account of the affair as presented by General Lovell Rousseau to Secretary of State William H. Seward:
... The troops being promptly formed, were, at precisely half past three o'clock, brought to a 'present arms', the signal given to the Ossipee ... which was to fire the salute, and the ceremony was begun by lowering the Russian flag ... The United States flag ... was properly attached and began its ascent, hoisted by my private secretary (and son), George Lovell Rousseau, and again salutes were fired as before, the Russian water battery leading off. The flag was so hoisted that in the instant it reached its place the report of the big gun of the Ossipee reverberated from the mountains around ... Captain Pestchouroff stepped up to me and said, 'General Rousseau, by authority from his Majesty the Emperor of Russia, I transfer to the United States the Territory of Alaska' and in a few words I acknowledged the acceptance of the transfer, and the ceremony was at an end.

The official celebration is held in Sitka, where schools release students early, many businesses close for the day, and events such as a parade and reenactment of the flag raising are held.