The United States District Courts are the trial courts of the federal court system. Within limits set by Congress and the Constitution, the District Courts have jurisdiction to hear nearly all categories of federal cases, including both civil and criminal matters.

District Court Judges are nominated by the President and confirmed by the United States Senate, as stated in Article III of the Constitution. The Senate Judiciary Committee typically conducts confirmation hearings for each nominee. District Judges are appointed for a life term, and may take senior status when they reach the following age and service requirements: age + years of service equal 80, at least 65 years old, and at least 10 years of service. Senior Judges continue to provide substantial service to the Court, but may choose to have a reduced case load or restrict the types of cases they hear. The U.S. District Court for the Southern District of Iowa has three District Judges and three Senior Judges.

U.S. Magistrate Judges are judicial officers of the District Court and are appointed by majority vote of the active District Judges of the Court to exercise jurisdiction over matters assigned by statute as well as those delegated by the District Judges. A full-time Magistrate Judge serves a term of eight years, and may be appointed to additional terms. Duties assigned to Magistrate Judges by District Court Judges may vary considerably from court to court. The U.S. District Court for the Southern District of Iowa has three Magistrate Judges.