The addition of new states to the Union between 1866 and 1912 made the Eighth Circuit the largest in the nation, consisting of 13 states covering a very large geographic area. Fearing that such a large circuit threatened the efficient administration of justice, Congress divided the circuit, moving Wyoming, Colorado, Utah, New Mexico, Oklahoma, and Kansas into the newly-created Tenth Circuit, and leaving Arkansas, Missouri, Iowa, Minnesota, Nebraska, North Dakota, and South Dakota in the Eighth Circuit. At the same time, the total number of circuit judgeships serving these states was increased from six to nine, with five in the Eighth Circuit and four in the Tenth.

See also:

Landmark Legislation: Tenth Circuit

Federal Judicial Circuits (charts)

Federal Judicial Circuits (map)