Which 1789 U.S. law established the first federal court system?

The Judiciary Act of 1789 established the first federal court system in the United States.

The Constitution’s Article III created a Supreme Court but left Congress to determine the structure and operation of the lower federal courts. The First Congress addressed that gap by passing the Judiciary Act, which President George Washington signed on September 24, 1789. Oliver Ellsworth of Connecticut was its principal author.

The law organized 13 judicial districts across the 11 states that had then ratified the Constitution. It created district courts and circuit courts, and it initially set the Supreme Court’s membership at one chief justice and five associate justices. The act also helped define federal jurisdiction and the relationship between federal and state courts.

A later section granting the Supreme Court certain original jurisdiction was declared unconstitutional in Marbury v. Madison. That case made the act especially important in the development of judicial review, although the statute itself was primarily a court-organization law.