The Supreme Court is the highest court in the federal Judiciary. Congress has established two levels of federal courts under the Supreme Court: the trial courts and the appellate courts.
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. There are 94 federal judicial districts, including at least one district in each state, the District of Columbia and Puerto Rico.
The 94 judicial districts are organized into 12 regional circuits, each of which has a United States court of appeals. A court of appeals hears appeals from the district courts located within its circuit, as well as appeals from decisions of federal administrative agencies.