U.S. #957 commemorates the 100th anniversary of Wisconsin’s admission to the Union. The stamp pictures the state capitol and an outline of Wisconsin. Wisconsin Becomes 30th State On May 29, 1848, Wisconsin was admitted as America’s 30th state. When the first European explorers arrived in Wisconsin during the early 1600s, the main Indian tribes were the Winnebago, Dakota, and Menominee. Within the next 100 years, many other Native American groups moved into the region after being pushed from their lands in the East by whites – or to escape the warring Iroquois League. These tribes included the Sauk, Fox, Ottawa, Kickapoo, Huron, Miami, Illinois, and Potawatomi.