The boundaries of the judicial circuits changed many times throughout the nineteenth century as the country expanded across the continent.  The original Ninth Circuit was created in 1837 and comprised Arkansas, Louisiana, Mississippi, and Alabama.  In 1855 Congress created the Circuit Court for the Districts of California and appointed Matthew McAllister as the first federal appellate judge in the west.  In 1863, after Judge McAllister’s resignation, Congress abolished the Circuit Court for California and created the Tenth Circuit, consisting of California and Oregon (which had become a state in 1859).  In 1866, after the Civil War, Congress again reorganized the circuits and put California, Oregon, and Nevada (which had become a state in 1864) in a new Ninth Circuit.  Montana and Washington were added in 1889 when they became states, then Idaho in 1890. 

          In 1891 Congress established the current federal court system, dividing the country into nine circuits with roughly equal populations.  A new Circuit Court of Appeals with three judges was created in each circuit, partly to relieve the Supreme Court of its appellate burden and to clarify the duties of each court.  The Territory of Hawaii was added to the Ninth Circuit in 1900, the Arizona Territory in 1912 when it became a state, then Alaska and Guam in 1960, followed by the Northern Mariana Islands in 1980. 

          The federal circuit courts vary in size and number of judges, but the Ninth Circuit is by far the largest.  The Ninth Circuit includes fifteenth district (trial) courts, thirteen bankruptcy courts, and the Court of Appeals. Geographically it is not just the western-most circuit, but the eastern-most, northern-most, and southern-most as well.  During the twentieth century the other two large original circuits split – the Eight Circuit became the Eighth and Tenth Circuits, and the Fifth Circuit became the Fifth and Eleventh Circuits. 

          Today the Ninth Circuit is the largest of the twelve regional circuits in geography, population, volume of litigation, and number of federal judges. The active circuit judge count in the other circuits ranges from six to seventeen, while the Ninth Circuit currently has twenty-nine active circuit judges. All circuits also include senior judges – judges who have semi-retired and no longer occupy an active judge’s seat, but still decide cases and contribute to their court. The Ninth Circuit currently has twenty-four senior circuit judges. In 2022, 8,268 new appeals were filed in the Ninth Circuit out of 40,869 nationally, which is 20.2% of all cases filed in the 12 circuit courts. The next largest, the Fifth Circuit, received 14.1% of national filings. Additionally, the Ninth Circuit had by far the highest percentage of immigration cases nationally, 56%.