The courts of the United States are closely linked hierarchical systems of courts at the federal and state levels. The federal courts form the judicial branch of the U.S. government and operate under the authority of the United States Constitution and federal law. The state and territorial courts of the individual U.S. states and territories operate under the authority of the state and territorial constitutions and state and territorial law.
Federal statutes that refer to the "courts of the United States" are referring only to the courts of the federal government, and not the courts of the individual states and counties. Because of the federalist underpinnings of the division between sovereign federal and state governments, the various state court systems are free to operate in ways that vary widely from those of the federal government, and from one another. In practice, however, every state has adopted a division of its judiciary into at least two levels, and almost every state has three levels, with trial courts hearing cases which may be reviewed by appellate courts, and finally by a state supreme court. A few states have two separate supreme courts, with one having authority over civil matters and the other reviewing criminal cases. 47 states and the federal government allow at least one appeal of right from a final judgment on the merits, meaning that the court receiving the appeal must decide the appeal after it is briefed and argued properly. Three states do not provide a right to a first appeal. Rather, they give litigants only a right to petition for the right to have an appeal heard.
State courts often have diverse names and structures, as illustrated below. State courts hear about 98% of litigation; most states have courts of special jurisdiction, which typically handle minor disputes such as traffic citations, and courts of general jurisdiction responsible for more serious disputes.[1]
The U.S. federal court system hears cases involving litigants from two or more states, violations of federal laws, treaties, and the Constitution, admiralty, bankruptcy, and related issues.[2] In practice, about 80% of the cases are civil and 20% criminal.[1] The civil cases often involve civil rights, patents, and Social Security while the criminal cases involve tax fraud, robbery, counterfeiting, and drug crimes.[1] The trial courts are U.S. district courts, followed by United States courts of appeals and then the Supreme Court of the United States. The judicial system, whether state or federal, begins with a court of first instance, whose work may be reviewed by an appellate court, and then ends at the court of last resort, which may review the work of the lower courts.[3]
Institutions which may be considered courts of the United States are listed below.