Columbia is the capital city of the U.S. state of South Carolina. With a population of 136,632 at the 2020 census, it is the second-most populous city in South Carolina. The city serves as the county seat of Richland County, and a portion of the city extends into neighboring Lexington County. It is the center of the Columbia, SC Metropolitan Statistical Area, which had an estimated population of 858,302 in 2023, and is the 70th-most populous metropolitan statistical area in the United States. The name Columbia is a poetic term used for the United States, derived from the name of Christopher Columbus, who explored for the Spanish Crown. Columbia is often abbreviated as Cola, leading to its nickname as "Soda City". The city is located just northwest of the geographic center of South Carolina and was the center of population of South Carolina in 2020. It is also the primary city of the Midlands region of the state. It lies at the confluence of the Saluda River and the Broad River, which merge at Columbia to form the Congaree River. As the state capital, Columbia is the site of the South Carolina State House, the center of government for the state. In 1860, the South Carolina Secession Convention took place in Columbia; delegates voted for secession, making South Carolina the first state to leave the Union in the events leading up to the Civil War. Columbia is home to the University of South Carolina, the state's flagship public university and the largest in the state. The area has benefited from Congressional support for Southern military installations. Columbia is the site of Fort Jackson, the largest United States Army installation for Basic Combat Training. Twenty miles to the east of the city is McEntire Joint National Guard Base, which is operated by the U.S. Air Force and is used as a training base for the 169th Fighter Wing of the South Carolina Air National Guard.