In the mid- to late-18th century, large groups of Scots and Ulster-Scots (later called the Scots-Irish) immigrated and settled in the back country of Appalachia and the Piedmont. They were the largest group of colonists from the British Isles before the American Revolution. In a census taken in 2000 of Americans and their self-reported ancestries, areas where people reported 'American' ancestry were the places where, historically, many Scottish, Scotch-Irish and English Borderer Protestants settled in America: the interior as well as some of the coastal areas of the South, and especially the Appalachian region. The population with some Scots and Scots-Irish ancestry may number 47 million, as most people have multiple heritages, some of which they may not know.