The Des Moines metropolitan area, officially known as the Des Moines–West Des Moines, IA Metropolitan Statistical Area (MSA) is located at the confluence of the Des Moines River and the Raccoon River. Des Moines serves as the capital and largest city of the U.S. state of Iowa. The metro area consists of six counties in central Iowa: Polk, Dallas, Warren, Madison, Guthrie, and Jasper. The Des Moines–Ames–West Des Moines Combined Statistical Area (CSA) encompasses the separate metropolitan area of Ames, and the separate micropolitan area of Boone. The Des Moines area is a fast-growing metro area.