The Constitution of the State of Wisconsin is the governing document of the U.S. State of Wisconsin. It establishes the structure and function of state government, describes the state boundaries, and declares the rights of state citizens. The Wisconsin Constitution was written at a constitutional convention held in Madison, Wisconsin in December 1847 and approved by the citizens of Wisconsin Territory in a referendum held in March 1848. Wisconsin was admitted to the United States on May 29, 1848. Although it has been amended over a hundred times, the original constitution ratified in 1848 is still in use. This makes the Wisconsin Constitution the oldest U.S. state constitution outside of New England. Only Massachusetts, New Hampshire, Vermont, Maine, and Rhode Island use older constitution