National Oklahoma Day Date in the current year: June 7, 2025

Oklahoma is a landlocked state in the West South Central region of the United States. It is bordered by Arkansas, Colorado, Kansas, Missouri, New Mexico, and Texas. Its name comes from the Choctaw language: okla means “people”, and humma means “red”. Thus, it can be interpreted as “the Land of the Red People”. Oklahoma’s official nickname is the Sooner State, a reference to Sooners, illegal settlers who entered the Unassigned Lands before the Oklahoma Land Rush of 1889.

Prior to the arrival of Europeans, the territory that is now Oklahoma was inhabited by various Indigenous peoples. The first Europeans to set foot in the area were Spanish explorers led by Francisco Vázquez de Coronado in 1541, but they did not claim the area. From the early 18th century to 1802, the region was claimed by the French, who sold their territory west of the Mississippi to the United States in the Louisiana Purchase.

In 1809, the territory of present-day Oklahoma became part of Arkansas Territory. In 1830, the United States government began forcibly resettling the so-called “Five Civilized Tribes” (Cherokee, Chickasaw, Choctaw, Muscogee, and Seminole) from the Southeast to the area including present-day Oklahoma. The area set aside for their relocation was referred to as Indian Territory. In 1890, the western half was organized as Oklahoma Territory, while the eastern half remained under Native American rule.

In the late 19th century, white settlers began illegally settling in Indian Territory. Their increased presence led to the adoption of the Curtis Act of 1898, which eliminated tribal land ownership and opened millions of acres to white settlement on a first-come, first-served basis in the so-called land runs (land rushes).

In an attempt to secure statehood for Indian Territory, representatives of the Five Civilized Tribes organized the Sequoyah Constitutional Convention in 1905 and proposed the name “Sequoyah” for the state. However, instead of granting statehood to Indian Territory, Congress insisted on joint statehood for Indian Territory and Oklahoma Territory.

On June 16, 1906, President Theodore Roosevelt signed the Oklahoma Enabling Act, which provided for the territories’ admission to the Union as a single state. A constitutional convention was held in Guthrie the following year, and Oklahoma was admitted to the Union as the 46th state on November 16, 1907.

In 2017, National Day Calendar founded the National State Days project to celebrate the diverse cultures and histories of each state in the order they joined the Union. However, national state days founded by National Day Calendar do not coincide with the respective states’ admission anniversaries. For example, National Oklahoma Day is celebrated on June 7, even though Oklahoma was admitted to the Union in November.