The state's 99 counties are governed by boards of supervisors. In general, county officials, including auditor, treasurer, recorder, and sheriff, are elected to four-year terms. They enforce state laws, collect taxes, supervise welfare activities, and manage roads and bridges.
Local government was exercised by 948 municipal units in 2002. The mayor-council system functioned in the great majority of these municipalities, though some of the larger cities employ the council-manager or commission system. Iowa's towns and cities derive their local powers from the state constitution, but the power to tax is authorized by the state general assembly. In 2002 there were 386 public school districts and 542 special districts.