Polk County, Iowa

Polk County is a county in the U.S. state of Iowa. As of the 2010 census, 430,640 people lived there. It the most populous county in Iowa. The county seat is Des Moines. Des Moines is also the capital city of Iowa. Polk County is one of the five counties that make up the Des Moines-West Des Moines Metropolitan Statistical Area.
History.
Polk County was formed on January 13, 1846. It was named after President James K. Polk. The first courthouse was built in 1846. Construction of a second courthouse was begun in 1858. It was finished in 1866.
Geography.
The county has a total area of . Of this, (or 96.19%) is land and (or 3.81%) is water. The county is bisected by the Des Moines River