Sooners

right|thumb|375px|Unassigned Lands – 1885 Sooners is the name given to settlers who entered the Unassigned Lands illegally in what is now the state of Oklahoma before the official start of the Land Rush of 1889. The Unassigned Lands were a part of Indian Territory that, after a lobbying campaign, were to be opened to American settlement in 1889. President Benjamin Harrison officially proclaimed the Unassigned Lands open to settlement on April 22, 1889. As people lined up around the borders of the Oklahoma District, they waited for the official opening. It was not until noon that it officially was opened to settlement. The name derived from the "sooner clause" of Proclamation 288 — Opening to Settlement Certain Lands in the Indian Territory, which stated that anyone who entered and occupied the land prior to the opening time would be denied the right to claim land.

The designation "Sooner" had a very negative connotation. While "Boomers" were merely expressing pioneer spirit in their desire to take land, Sooners were essentially stealing from those arriving with the legally authorized period. However, these negative connotations cooled as time passed after 1889 and land claims were settled. In 1908, the University of Oklahoma football team adopted the nickname "Sooners". The U.S. state of Oklahoma has adopted the nickname the "Sooner State" since the 1920s.