Oklahoma's earliest history is defined by pre-Columbian indigenous populations, most notably the Spiro Mounds builders (a Mississippian culture) who created an advanced trading network between 850 and 1450 CE. In the 16th century, European explorers, including Francisco Vásquez de Coronado, passed through the region, followed centuries later by French fur trappers who left a lasting mark on the area's geography through place names.
The 1830s brought a dark and transformative era to the region. The U.S. government's Indian Removal Act forced the relocation of the "Five Civilized Tribes" (Cherokee, Chickasaw, Choctaw, Creek, and Seminole) and other eastern tribes to the region via the devastating Trail of Tears. The area became known as "Indian Territory." During the American Civil War, the tribes were fractured, with some aligning with the Confederacy and others with the Union, leading to further punitive treaties post-war that forced tribes to cede western lands.
In 1889, the U.S. government opened these unassigned western lands to white settlement via the first of several dramatic Land Runs. Settlers who crossed the borders before the official start time were dubbed "Sooners," giving the state its famous nickname. The Twin Territories (Oklahoma Territory and Indian Territory) were merged and admitted to the Union as the 46th state on November 16, 1907.
The 20th century saw the discovery of vast oil reserves, creating incredible wealth and leading to a booming energy industry. However, it was also marked by deep racial and environmental tragedies, including the 1921 Tulsa Race Massacre—where a prosperous Black community known as "Black Wall Street" was destroyed by a white mob—and the devastation of the Dust Bowl in the 1930s, which triggered a mass migration of "Okies" westward. Modern Oklahoma has continued to evolve, overcoming tragedies like the 1995 Oklahoma City bombing to build revitalized, culturally diverse urban centers.