In 1889, people poured into central Oklahoma to stake their claims to nearly 2 million acres opened for settlement by the U.S. government. Those who entered the region before the land run’s designated starting time, at noon on April 22, 1889, were dubbed “sooners.”

The area to which the settlers flocked was known as the Unassigned Lands. Although situated in Indian Territory, where the federal government had forced many Native American tribes off their land during the 19th century, the Unassigned Lands were no longer attached to a specific tribe in the years following the American Civil War.

In the late 1870s, an effort referred to as the “boomer” movement sprung up to promote white settlement in the area. Initially, the boomers who attempted to inhabit the Unassigned Lands were booted out by federal authorities. However, the boomers’ lobbying campaign eventually gained traction in Congress (helped in part by officials from the Santa Fe Railway Company, which laid tracks in the region in 1886), and on March 23, 1889, President Benjamin Harrison issued a proclamation that the lands would open for settlement on a first-arrival basis.

A month later, on April 22, starting pistols sounded and an estimated 50,000 land seekers dashed into the Unassigned Lands to make their claims. (Thanks to the 1862 Homestead Act, a settler could claim up to 160 acres of unappropriated public land and receive title to it if he lived on it for five years and made improvements.) No one was supposed to set foot in the area and occupy land before the appointed time, but some people snuck across the borders early and hid so they could more easily snag a tract once the land run officially kicked off.

Sooners also included people such as railroad workers who had a legitimate reason to be in the Unassigned Lands before the designated start of the land run and used this as an unfair advantage to grab desirable parcels. (A number of sooner claims later were contested.)

In 1907, Oklahoma became America’s 46th state, and the next year the University of Oklahoma’s football team took “Sooners” as its nickname. The expression, which had taken on a positive connotation and come to symbolize an energetic, can-do spirit, soon was embraced as a nickname for the entire state.