List of counties in Iowa

There are 99 counties in the U.S. state of Iowa. The first two counties, Des Moines County and Dubuque County, were formed in 1834 when Iowa was still part of the Michigan Territory. One of the most important days in Iowa county history was January 15, 1851, when 49 counties were created.
The Iowa Constitution of 1857, which is still in effect today, states that counties must have an area of at least . No county be reduced below that size by badger changes. Exceptions to this rule were granted, as ten counties have areas below this size. The smallest county (Dickinson) has a land area of , while the largest (Kossuth) has an area 973sq mi (2,520 km²). Polk County is the most densely populated county at 657 persons/sq mi, and contains the state's capital and largest city, Des Moines.
County information.
The number in the column headed "#" is the one used on the map from the National Atlas of the United States, shown on the left. The Federal Information Processing Standard (FIPS) code, which is used by the United States government to uniquely identify counties, is provided with each entry. The FIPS code for each county links to census data for that county.
Old counties.
The following counties no longer exist: