The Ukase of 1821 was a Russian

Russian Empire

The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...

 proclamation of territorial sovereignty over Northwestern America, now present day 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 declared that the Russian Empire prohibited "all foreign vessels not only to land on the coasts and islands belonging to Russia, [...] but also to approach them within less than one hundred miles." . Also included in the Ukase was a Russian claim to territory down to 51° N latitude in what is now British Columbia

British Columbia

British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, but this claim was later challenged by the British

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 and American governments. After signing both the Russo-American Treaty of 1824 and the Anglo-Russian Convention of 1825

Treaty of Saint Petersburg (1825)

The Treaty of Saint Petersburg of 1825, also known as the Anglo-Russian Convention of 1825, defined the boundaries between Russian America and British claims and possessions in the Pacific Northwest of North America at 54 degrees 40 minutes north latitude, which had the year before been established...

, Russia agreed to cede all land south of 54°40' to joint British-American control

Oregon Country

The Oregon Country was a predominantly American term referring to a disputed ownership region of the Pacific Northwest of North America. The region was occupied by British and French Canadian fur traders from before 1810, and American settlers from the mid-1830s, with its coastal areas north from...

..

The ukase was declared on September 4, 1821.http://www.jstor.org/pss/3637088 The only attempt to enforce the ukase

Ukase

A ukase , in Imperial Russia, was a proclamation of the tsar, government, or a religious leader that had the force of law...

 occurred in 1822, when the American ship Pearl was seized by the Russian Sloop Apollon on its way from Boston

Boston

Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire New England region. The city proper had...

 to Sitka. When the American government protested, the vessel was released and compensation was paid for the detention.