Oklahoma County Map: All 77 Counties

In McGirt v. Oklahoma (591 U.S. 894), Justice Neil Gorsuch wrote for the Court that Congress had never disestablished the 1866 reservation boundaries of the Muscogee (Creek) Nation. Subsequent rulings extended this recognition to the Cherokee, Choctaw, Chickasaw, Seminole, and Quapaw nations, encompassing nearly the entire eastern half of Oklahoma across dozens of counties, including the city of Tulsa.

Under the Major Crimes Act (18 U.S.C. § 1153), major felony crimes involving enrolled tribal members committed within these reservation boundaries fall under exclusive federal or tribal court jurisdiction rather than county district courts.

To ensure seamless community protection, county commissioners, sheriffs, and municipal police entered into extensive cross-deputization agreements with tribal marshals and the FBI, allowing county law enforcement officers to enforce both tribal, state, and federal laws across county lines.

The Oklahoma Panhandle—comprising Cimarron, Texas, and Beaver counties—was originally known as "No Man's Land" or the Public Land Strip. Established as an unorganized territory because the Missouri Compromise of 1820 forbade slavery north of latitude 36°30'N, Texas surrendered this 168-mile strip of land upon entering the Union in 1845.

Cimarron County at the western tip is the only county in the entire United States that touches four other states: Texas, New Mexico, Colorado, and Kansas. It also contains Oklahoma's highest natural point at Black Mesa (4,973 ft).

In north-central Oklahoma, Osage County spans 2,251 square miles—the largest county in Oklahoma and entirely coterminous with the Osage Nation reservation. Known for its vast tallgrass prairie reserves, historic oil wealth, and tragic 1920s murders chronicled in "Killers of the Flower Moon," Osage County manages its infrastructure through a unique collaboration between county commissioners and the Osage Minerals Council.