is a city in Dane County in the U.S. state of Wisconsin. Located east of Madison it is part of the Madison Metropolitan Statistical Area. As of the 2000 census, the city's population was 20,369 and was expected to double in size by 2020 to around 40,000. It is the sixth-fastest growing city in Wisconsin, and the fastest-growing among cities of 10,000 or more, growing an estimated 23.6% between 2000 and 2006.
President Martin Van Buren commissioned a party of 45 men, including Augustus A. Bird, to build a territory capitol in Madison. The group of men left Milwaukee on May 26 1837, and traveled for days in the rain. On June 9, the group emerged at the edge of the prairie and with the sun shining for the first time in days, carved the words "Sun Prairie" into a tree. Charles Bird returned to the area two years later and became the first settler.
The Town of Sun Prairie was created on February 2 1846. The city of Sun Prairie, which grew from that town, was incorporated in 1958.