There are thirteen U.S. Courts of Appeals including eleven numbered circuits which have regional jurisdiction, a District of Columbia Circuit, and the Court of Appeals for the Federal Circuit located in Washington, D.C. These courts hear appeals from the U.S. District Courts. Federal appeals court opinions are binding on U.S. District Courts within the circuit and may be appealed to the U.S. Supreme Court.
The trial court and court of original jurisdiction in the federal system is the United States District Court. District Courts hear civil and criminal cases arising under federal law and cases where citizens of two or more states are in conflict. At least one district, usually more, exists in each state. District Courts usually do not extend across state lines.