History of Polk County
Polk County was formed on January 13, 1846 and organized on March 1, 1846., the legislative body of the Iowa Territory authorized the creation of twelve counties in the Territory, with general descriptions of their boundaries. On January 17 they further enacted a resolution setting the effective date of the county government for Jasper and Polk Counties as March 1, 1846. Polk County's name referred to United States President James K. Polk, who served from 1845 to 1849. The first courthouse, a two-story structure, was built in Des Moines in 1846. Rapid settlement and commercial growth in the county soon rendered this building insufficient, so construction of a larger building was initiated in 1858. Due to construction delays and the onset of the Civil War, the structure was not completed until 1866.
Adapted from Wikipedia, CC BY-SA 4.0.