Severe reduction of Native American populations in the contiguous United States, mostly because of new infectious diseases carried by European colonists, combined with genocidal warfare Forced migration Deportation and flight of United Empire Loyalists to Canada, the Caribbean, and Britain after the American Revolution Forced removal of more than one million African Americans in the domestic slave trade from the Upper South to the Deep South during the early 19th century as Americans developed new lands for plantations Territorial conflict with Native Americans and the Indian removal policy of the 19th century displaced many remaining native populations from east of the Mississippi River to territories to the west, especially to what is now Oklahoma. Immigration Historical immigration to the United States from all countries of the world and throughout the history of the country, for religious, political and economic reasons. Since the late 19th century, the History of laws concerning immigration and naturalization in the United States and illegal immigration to the United States have influenced the ethnic balance of that immigration. Various groups have been denied entry due to discrimination, economic protectionism, and political conflict with their nation of origin. Other groups have received favored status, such as refugees and nationals of allied nations. Transatlantic migrations from Europe, especially in the 19th century, created ethnic enclaves in many eastern cities and settling many rural areas east of the Mississippi Immigration from Asia has had the most influence on Hawaii and the West Coast, but has also created predominantly Asian neighborhoods in many major cities across the country. Immigration from Mexico and other existing Latino populations has strongly influenced the Southwest. Westward expansion of the United States The Royal Proclamation of 1763 restricted the western boundary of European settlement to the watershed east of the Appalachian Mountains; despite the Confederation Congress Proclamation of 1783 and Nonintercourse Acts prohibiting private purchase of Native American lands, the territory between the Mississippi River and Appalachian Mountains granted to the United States by the Treaty of Paris of 1783 was gradually opened to White settlers through public purchase of Indian lands. The Homestead Act promoting settlement west of the Mississippi after the Louisiana Purchase Settlement of Utah by members of the Church of Jesus Christ of Latter-day Saints California Gold Rush Oregon Trail Klondike Gold Rush promoting settlement of Alaska Internal migration African Americans escaped from slavery, sometimes via the Underground Railroad, reaching the