America’s settlement of its western frontier had for a century followed a pattern of steady migration that gradually filled up an area, built up towns, and pushed back the Indians. On April 22 the first Oklahoma settlers telescoped this process into one frenzied afternoon.

The Indian Removal Act of 1830 had transplanted eastern Indian tribes at great hardship into what is now Oklahoma, a land that no white settlers wanted. The Indians brought with them President Andrew Jackson’s promise that the land would belong to them “as long as the grass grows, or water runs.”

Only fifty years later the tribes faced settlers known as Boomers, who had changed their minds about the territory and were being chased out regularly by the U.S. Army. By the time Benjamin Harrison became President in 1889, the Boomers were demanding that all of the Indian Territory be opened up to them. In March the federal government bent to their will by issuing a law empowering it to buy from the Indians two million acres in the center of the territory, an unsettled area that had been set aside for Indian tribes that never arrived. White settlement in this district would become legal at noon on April 22; cavalry gunshots would be the signal for settlers to swarm into the territory to attempt to claim free 160-acre plots of their own.

The country had never seen a spectacle like “Harrison’s Hoss Race.” The army of one hundred thousand hopeful homesteaders who had been milling around the borders of the unoccupied territory burst forth in a ragtag wave of horses, trains, wagons, and even bicycles. “It seemed as if some thousands of human beings had gone mad,” remembered one pioneer. The first Boomers arrived at the site of Oklahoma City at 12:40 P.M. ; within a few hours the bare expanse of prairie had become a tent city of ten thousand people.

The homesteaders faced long odds. There was only one plot for every ten Boomers, and many who thought they had staked claims to legitimate plots were later forced out when streets were surveyed. Further reducing their chances were the Sooners, who earned their nickname by sneaking into the territory before the signal, hiding near choice plots, and claiming them before anyone else arrived. Though for years Sooner was synonymous with treachery among Oklahomans, ultimately they would salute their roguish ancestors by naming Oklahoma the Sooner State.

By nightfall of April 22 thousands of feet, hooves, and wheels had trampled the territory’s prairie grasses and flowers into mulch. Further land runs, erosion, and the plow carved up so much forest and grassland by the time of statehood in 1907 that the Oklahoma native Will Rogers would remark that “we spoiled the best Territory in the world to make a State.”