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.[1] The Act became effective on March 3, 1863, during the Lincoln administration.
Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the supreme court of the United States shall hereafter consist of a chief justice and nine associate justices, any six of whom shall constitute a quorum; and for this purpose there shall be appointed one additional associate justice of said court, with the like powers, and to take the same oaths, perform the same duties, and be entitled to the same salary, as the other associate justices.
— Tenth Circuit Act of 1863