The number of Americans of Scottish descent today is estimated to be 20 to 25 million (up to 8.3% of the total US population), and Scotch-Irish, 27 to 30 million (up to 10% of the total US population), the subgroups overlapping and not always distinguishable because of their shared ancestral surnames.
The majority of Scotch-Irish Americans originally came from Lowland Scotland and Northern England before migrating to the province of Ulster in Ireland (see Plantation of Ulster) and thence, beginning about five generations later, to North America in large numbers during the eighteenth century.
The table shows the ethnic Scottish population in the United States from 1700 to 2013. In 1700 the total population of the American colonies was 250,888 of which 223,071 (89%) were white and 3.0% were ethnically Scottish. In the 2000 census, 4.8 million Americans self-reported Scottish ancestry, 1.7% of the total US population. Another 4.3 million self-reported Scotch-Irish ancestry, for a total of 9.2 million Americans self-reporting some kind of Scottish descent.
Self-reported numbers are regarded by demographers as massive under-counts, because Scottish ancestry is known to be disproportionately under-reported among the majority of mixed ancestry, and because areas where people reported “American” ancestry were the places where, historically, Scottish and Scotch-Irish Protestants settled in America (that is: along the North American coast, Appalachia, and the Southeastern United States). Scottish Americans descended from nineteenth-century Scottish immigrants tend to be concentrated in the West, while others in New England are the descendants of immigrants from the Maritime Provinces of Canada, especially in the 1920s. Americans of Scottish descent outnumber the population of Scotland, where 4,459,071 or 88.09% of people identified as ethnic Scottish in the 2001 Census.
Just for a little wider perspective.
I myself can and do (proudly) claim Scottish ancestry, along with a variety of others.
Perhaps my favorite Scots American:
John Muir (/mjʊər/; April 21, 1838 – December 24, 1914) also known as “John of the Mountains”, was a Scottish-American naturalist, author, environmental philosopher and early advocate of preservation of wilderness in the United States. His letters, essays, and books telling of his adventures in nature, especially in the Sierra Nevada of California, have been read by millions. His activism helped to preserve the Yosemite Valley, Sequoia National Park and other wilderness areas. The Sierra Club, which he founded, is a prominent American conservation organization. The 211-mile (340 km) John Muir Trail, a hiking trail in the Sierra Nevada, was named in his honor. Other such places include Muir Woods National Monument, Muir Beach, John Muir College, Mount Muir, Camp Muir and Muir Glacier. In Scotland, the John Muir Way, a 130-mile-long route, was named in honor of him.
In his later life, Muir devoted most of his time to the preservation of the Western forests. He petitioned the U.S. Congress for the National Park bill that was passed in 1890, establishing Yosemite National Park. The spiritual quality and enthusiasm toward nature expressed in his writings inspired readers, including presidents and congressmen, to take action to help preserve large nature areas. He is today referred to as the “Father of the National Parks” and the National Park Service has produced a short documentary about his life.
Muir has been considered “an inspiration to both Scots and Americans”. Muir’s biographer, Steven J. Holmes, believes that Muir has become “one of the patron saints of twentieth-century American environmental activity,” both political and recreational. As a result, his writings are commonly discussed in books and journals, and he is often quoted by nature photographers such as Ansel Adams. “Muir has profoundly shaped the very categories through which Americans understand and envision their relationships with the natural world,” writes Holmes. Muir was noted for being an ecological thinker, political spokesman, and religious prophet, whose writings became a personal guide into nature for countless individuals, making his name “almost ubiquitous” in the modern environmental consciousness. According to author William Anderson, Muir exemplified “the archetype of our oneness with the earth”, while biographer Donald Worster says he believed his mission was “…saving the American soul from total surrender to materialism.”:403 On April 21, 2013, the first ever John Muir Day was celebrated in Scotland, which marked the 175th anniversary of his birth, paying homage to the conservationist.