At statehood, only 10 nationalities were represented in Wisconsin; by 1950, more than 50 could be counted. The vast majority of these were European, and Wisconsin is still 88 percent Caucasian.

A decidedly German state, Wisconsin boasts more residents claiming Teutonic roots (54 percent) than anywhere else in the country. So thick is the German milieu of Milwaukee (34 percent) that German chancellors visit the city when they’re in the United States for presidential summits. Wisconsin has more than 50,000 native speakers of German—quite remarkable for a century-old ethnic group. Germans came in three waves. The first arrived 1820–1835 from both Pennsylvania and southwestern Germany. The second wave, 1840–1860, came mostly from northwest Germany and included the legendary "48ers"—enlightened intellectuals fleeing political persecution. During this wave, as many as 215,000 Germans moved to Wisconsin each year; by 1855, fully one-third of Wisconsin’s Germans had arrived. The third wave occurred after 1880 and drew emigrants mainly from Germany’s northeastern region to southeastern Wisconsin, where they worked in the burgeoning factories.

The state’s French roots can be traced back to the voyageurs, trappers, and Jesuit priests. They started the first settlements, along the Fox and Wisconsin River Valleys. Though Wisconsin shows no strong French presence in anything other than place-names, the Two Rivers area still manifests an Acadian influence.

As the British and the French haggled and warred over all of the Wisconsin territory, many crown-friendly British Yankees did move here, populating virtually every community. The Irish began arriving in the late 19th century in numbers second only to the Germans. Irish influence is found in every community, especially Milwaukee’s Bay View, Erin in Washington County, Ozaukee County, Adell and Parnell in Sheboygan County, and Manitowoc County.

Pockets of Welsh and Cornish are found throughout the state, the latter especially in the southwestern lead-mining region of the state. A distinct Belgian influence exists in Kewaunee County, where Walloon can still be heard in local taverns.

Poles represent the primary Eastern European ethnic group. The largest contingent is in Milwaukee, where kielbasa is as common a dietary mainstay as bratwurst. Most Poles arrived 1870–1910. At that time, Poland was not recognized as a country, so Ellis Island officials erroneously categorized many of the immigrants as Prussian, Austrian, or Russian. While 90 percent of Wisconsin’s Polish immigrants moved into the cities, about three-tenths of those who arrived farmed, mostly in Portage and Trempealeau Counties; the latter is the oldest Polish settlement in the United States. Czechs, another large Eastern European group, live mostly in north and east-central Wisconsin, especially Kewaunee and Manitowoc Counties.

Many Norwegians also emigrated to the Upper Midwest, primarily Minnesota and Wisconsin. Most were economic emigrants trying to escape Norway’s chronic overpopulation. Most Norwegians in Wisconsin wound up in Dane and Rock Counties. Finnish immigrants to the United States totaled 300,000 between 1864 and 1920, and many of these settled in the Upper Peninsula of Michigan and northern Wisconsin. Swedes made up the smallest Scandinavian contingent, the original settlement made up of a dozen families near Waukesha.

By the turn of the 20th century, Wisconsin was home to almost 10 percent of all the Danes in the United States—the second-largest national contingent. Most originally settled in the northeast (the city of Denmark lies just southeast of Green Bay), but later immigrants wound up farther south. To this day, Racine is nicknamed “Kringleville,” for its flaky Danish pastry.

The Dutch settled primarily in Milwaukee and Florence Counties beginning in the 1840s, when potato crops failed and protests flared over the Reformed Church. These southeastern counties today sport towns such as Oostburg, New Amsterdam, and Holland.

In 1846, a large contingent of Swiss from the Glarus canton sent emissaries to the New World to search out a suitable immigration site. Eventually, the two scouts stumbled upon the gorgeous, lush valleys of southwestern Wisconsin. A great deal of Swiss heritage remains in Green County.

Italians began arriving in the 1830s—many Genoese migrated north from Illinois lead camps to fish and scavenge lead along the Mississippi River—but didn’t arrive in substantial numbers until the early 1900s. Most settled in the southeast, specifically Milwaukee, Racine, and especially Kenosha.

Perhaps unique to Wisconsin is the large population of Icelandic immigrants, who settled on far-flung Washington Island, northeast of Door Peninsula. It was the largest single Icelandic settlement in the United States when they arrived in 1870 to work as fishers.