|Iowa joined the Union in 1846 to become the 29th state of the United States. It is situated in the Midwestern region of the country with Minnesota to the north, Missouri to the south, Nebraska and South Dakota to the west and Wisconsin and Illinois to the east. The Mississippi river, which separate the state from Illinois and Wisconsin, forms its natural boundary to the east. On the other hand, the Missouri river flowing through its western edge separates it from Nebraska. Another river, the Big Sioux forms the boundary line with South Dakota. There are many natural and man-made lakes in the state, such as Spirit Lake, Saylorville Lake, East Okoboji Lake, West Okoboji lake, Coralville Lake, Odessa, and Clear Lake. Iowa has an agriculture-based economy, which was founded by settlers from Western Europe and Scandinavia after Louisiana Purchase. The total area of the state is 56,272 with an estimated population of 3,002,555 in 2008. Nicknamed as the "Hawkeye State" and also the "Tall Corn State", Iowa is commonly referred to as the "American Heartland".The state of Iowa consists of 99 counties and Des Moines, the capital, is located in Polk County.