Until the early 19th century, Wisconsin was inhabited mainly by Indians; the French and British brought few permanent settlers. In the 1820s, southerners began to arrive from the lower Mississippi, and in the 1830s easterners poured in from New York, Ohio, Pennsylvania, and New England.

Foreign immigrants began arriving in the 1820s, either directly from Europe or after temporary settlement in eastern states. Most of the early immigrants were from Ireland and England. Germans also came in large numbers, especially after the Revolution of 1848, and by 1860 they were predominant in the immigrant population, which was proportionately larger than in any other state except California. The state soon became a patchwork of ethnic communities—Germans in the counties near Lake Michigan, Norwegians in southern and western Wisconsin, Dutch in the lower Fox Valley and near Sheboygan, and other groups in other regions.

After the Civil War, and especially in the 1880s, immigration reached new heights, with Wisconsin receiving a large share of Germans and Scandinavians. The proportion of Germans declined, however, as new immigrants arrived from Finland, Russia and from southern and eastern Europe, especially Poland, before World War I. Despite this overseas immigration, Wisconsin suffered a net population loss from migration beginning in 1900 as Wisconsinites moved to other states. Between 1970 and 1983 alone, this loss totaled 154,000. From 1985 to 1990, the net loss from migration amounted to 3,150. Between 1990 and 1998, Wisconsin had net gains of 84,000 in domestic migration and 21,000 in international migration. In 1998, 3,724 foreign immigrants arrived in Wisconsin; of these, the greatest number (680) came from Mexico. The state's overall population increased 6.8% between 1990 and 1998.

A significant trend since 1970 has been the decline in population in Milwaukee and other large cities; at the same time, suburbs have continued to grow, as have many other areas, especially in parts of northern Wisconsin. In the period 1995–2000, 338,108 people moved into the state and 330,826 moved out, for a net gain of 7,282.