The Tenth Circuit Act of 1863 (12 Stat. 794) was a federal statute which increased the size of the Supreme Court of the United States from nine justices to ten, and which also reorganized the circuit courts of the federal judiciary. The newly created Tenth Circuit consisted of California and Oregon, and addressed the judicial needs of the newly-created western states. The Act became effective on March 3, 1863, during the Lincoln administration. — Tenth Circuit Act of 1863