From the Oklahoma Historical Society - United States Court for the Indian Territory:

When Congress created Oklahoma Territory in 1890, the legislation reduced the size of Indian Territory and narrowed its definition to the lands occupied by the Five Tribes and the Indian tribes within the Quapaw Indian Agency. The legislation also gave the Indian Territory court jurisdiction of some federal felonies, including bootlegging, and of prosecutions for perjury, subornation of perjury, theft of court records, conspiracy to intimidate litigants, witnesses, or jurors, and conspiracy to obstruct the administration of justice. Thus, by 1890 the court's jurisdiction of criminal cases had expanded beyond only minor federal offenses.

The 1890 legislation created three divisions in the Indian Territory court but did not increase the number of judges. The First Division sat at Muskogee, the Second Division at South McAlester, and the Third Division at Ardmore. Two court terms were to be held each year in each division, and criminal cases were to be tried in the division in which the alleged offense occurred.

A watershed event for the Indian Territory court came about in 1895 when Congress gave the court jurisdiction of all criminal offenses committed in the territory. As of March 1, 1895, if the court had jurisdiction of a crime before 1895, its jurisdiction became exclusive. As of September 1, 1896, the court acquired "exclusive, original jurisdiction of all offenses, against the laws of the United States committed in said Territory," and the federal courts outside Indian Territory had no jurisdiction over crimes committed there. By this law the Indian Territory court acquired capital punishment jurisdiction.

The 1895 legislation divided the Indian Territory into three judicial districts: Northern, Central, and Southern. It also designated numerous court towns in each district and added two judges to the bench. The incumbent judge was assigned to the Central District, while new judgeships were assigned to the Northern and Southern. The legislation also created an Indian Territory Court of Appeals, but there was no separate appellate bench. The judges of the Indian Territory sat as the appellate court, the judge senior in commission serving as chief justice, and the judge trying the case at nisi prius not seating.

In 1897 Congress created a new judgeship for court, and in 1902 it increased the number of districts to four. Part of the old Northern District became the new Northern District, seated at Vinita. The remainder of the old Northern District became the new Western District, seated remaining at Muskogee. In 1904 Congress added four judgeships to the court. The incumbents of these did not have the power to appoint court personnel and did not sit on the court of appeals. In almost twenty years of existence, the Indian Territory court had fifteen judges. The United States Court for the Indian Territory Court continued in existence until 1907 statehood.