The Treaty of Paris officially recognized American independence, caused Britain to surrender most of its territory east of the Mississippi River to the United States, and established the US-Canada Border. The Canada-United States border is the longest international border in the world, at 8,891 km (5,525 mi) long. The land border contains two sections: Canada's border with the bordering United States to its south and the U.S. state of Alaska to its west. The border begins at the outlet of the Passamaquoddy Bay in the Atlantic Ocean and ends in the west where the Strait of Juan de Fuca meets the Pacific Ocean. Canada and the United States relationship has grown greatly since the border was established. For instance, Canada and the United States cooperate to manage the secure and efficient flow of goods and people across the border, which is essential to the countries' economic competitiveness and prosperity. As a result of irregular migration, Canada and the U.S. expanded the Safe Third Country Agreement (STCA) on March 25, 2023, to ensure fairness and more orderly migration between the two