The Supreme Court of the United States sits at the apex of the federal court system. It is made up of nine judges, known as justices, and is presided over by the Chief Justice. It sits in Washington, D.C. Parties who are not satisfied with the decision of a U.S. Circuit Court of Appeal (or, in rare cases, of a U.S. District Court) or a state supreme court can petition the U.S. Supreme Court to hear their case. This is done mainly by a legal procedure known as a Petition for a Writ of Certiorari (cert.). The Court decides whether to accept such cases. Each year, the Court accepts between 100 and 150 of the some 7,000 cases it is asked to hear for argument. The cases typically fit within general criteria for oral arguments. Four justices must agree to hear the case (grant cert). While primarily an appellate court, the Court does have original jurisdiction over cases involving ambassadors and two or more states.
There are 13 U.S. Circuit Courts of Appeal in the United States. These courts are divided into 12 regional circuits and sit in various cities throughout the country. The U.S. Court of Appeals for the Federal Circuit (the 13th Court) sits in Washington. With the exception of criminal cases in which a defendant is found not guilty, any party who is dissatisfied with the judgment of a U.S. District Court (or the findings of certain administrative agencies) may appeal to the U.S. Circuit Court of Appeal in his/her geographical district. These courts will examine the trial record for only mistakes of law; the facts have already been determined by the U.S. District Court. Therefore, the court usually will neither review the facts of the case nor take any additional evidence. When hearing cases, these courts usually sit in panels of three judges.
There are 94 U.S. District Courts in the United States. Every state has at least one district court, and some large states, such as California, have as many as four. Each district court has between 2 and 28 judges. The U.S. District Courts are trial courts, or courts of original jurisdiction. This means that most federal cases begin here. U.S. District Courts hear both civil and criminal cases. In many cases, the judge determines issues of law, while the jury (or judge sitting without a jury) determines findings of fact.