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.