The large Scottish and Scots-Irish immigration of the 18th century helped define the cultural patterns of the United States and Canada. Scots and Scots-Irish Americans were the fifth largest ethnic group in the United States in 2000, with only German, Irish, English, and Italian Americans being more numerous. Scots and Scots-Irish were the third most numerous group in Canada, behind only English and French Canadians. In the U.S. census of 2000, more than 9.2 million Americans claimed Scots or Scots-Irish descent; while in the Canadian census of 2001, 4,157,210 Canadians claimed Scottish ancestry. Being among the earliest settlers to North America and coming in very large numbers from the 18th century, by the 20th century Scots were integral to both American and Canadian identity and were scattered widely throughout both countries. By the time Canada took its first post-confederation census in 1871, 26 percent of Canadians were of Scottish descent, 24 percent Irish, and 20 percent English. By the time other immigrant groups overtook the British in numbers immigrating to the United States, around the turn of the 20th century, the British culture pattern had been firmly established as the American model (see British immigration; Irish immigration). In Canada, the early French enclave of Quebec became increasingly isolated as British customs and institutions took root throughout the remainder of Canada.
Scotland covers 30,414 square miles on the northern third of the island of Britain. England is its neighbor to the south. Scotland was an independent state on the island of Britain during the medieval period but fell under English influence from the 13th century as the two royal families became closely entwined through marriage. In 1603, with the death of Queen Elizabeth I, the Scottish king James IV also became king of England, as James I. The Scottish royal family, the Stuarts, was weakened as a result of the Glorious Revolution of 1688, and the Act of Union of 1707 made the kingdom of Scotland and the principality of Wales integral parts of a British empire under the United Kingdom of Great Britain. Gradually, Scots, especially in the southern lowlands, became more anglicized, and most converted to Presbyterianism. Many Highland Scots nevertheless retained their clan structure and Roman Catholicism and continued to support the ousted Stuart dynasty well into the 18th century.
Although Scots had been among the earliest immigrants to the Americas, the first widespread Scottish immigration to the New World came between 1717 and 1775, when more than 100,000 Presbyterian Scots-Irish settled in America, mainly because of high rents or famine and most coming from families who had been in Ireland for several generations (see Ulster). In the colonial period, these Scots-Irish were usually referred to simply as Irish, making it difficult to determine exact figures. Additionally, large numbers of rebellious Scots were exiled to America by the British government. But there was also a significant voluntary migration of Scots directly from Scotland, especially after 1730, with some 40,000 coming between 1763 and 1775 alone. Although Scots and Scots-Irish became prominent throughout the colonies, they frequently settled along the Appalachian frontier and largely influenced the religion and culture of the frontier regions as they developed. Altogether this represented the largest movement of any group from the British Isles to British North America in the 18th century.
Though the politics of the Napoleonic Wars (1803–15) limited immigration after the American Revolution (1775–83; see American Revolution and immigration), between 1783 and 1812 about 100,000 people immigrated from Ulster, most of them Scots-Irish. Thereafter, the immigration of the Scots-Irish became closely tied to the story of Irish immigration. The immigration of Scots from Scotland itself was redirected to Canada after the American Revolution. By the time of the first Canadian census in 1871, Scots totaled 26 percent of the population, compared to 24 percent Irish and 20 percent English. After 1850, however, Scottish immigration to the United States picked up, and by 1870, the United States once again became the predominant destination for Scots immigrating to the New World. Between 1870 and 1920, about 53 percent of all Scottish immigrants went to the United States. During the difficult economic crisis in the 1920s, about 160,000 Scots immigrated to the United States, with a large percentage from declining industries.
Agricultural consolidations in Scotland after 1870 led to an increase of agriculturalists immigrating to Canada, and Scots gradually began to fill the western prairies. By 1911, people of Scots ancestry constituted between 14 and 19 percent of the populations of Manitoba, Saskatchewan, Alberta, and British Columbia. Scots continued to immigrate in significant numbers throughout much of the 20th century, though exact figures are difficult to determine because figures on Scots were not separated from aggregate numbers coming from the United Kingdom.