By defeating Mexico in the U.S.-Mexican War (1846–48), the United States added virtually all of the present American Southwest to the Union, together with some 100,000 Mexican citizens.

U.S. Citizenship and Immigration Services (USCIS) is the agency within the DEPARTMENT OF HOMELAND SECURITY (DHS) responsible for providing services to immigrants and nonimmigrant visitors, including immigration admission...

From the establishment of the first permanent English settlement at Jamestown, Virginia (see Virginia colony), in 1607, the area now known as the United States has attracted more immigrants than any other country in the world.

Ulster, situated in the northeastern portion of the island of Ireland, was one of the major Irish kingdoms of the medieval period.

Ukrainian immigration to Canada represented the largest of any ethnic group from eastern Europe, and the Ukrainians in Canada are one of the few ethnic groups with a larger absolute population than their counterparts in the United States.