Little Rock is the capital and most populous city of the U.S. state of Arkansas. As the county seat of Pulaski County, the city was incorporated on November 7, 1831, on the south bank of the Arkansas River close to the state's geographic center. The city derives its name from a rock formation along the river, named the "Little Rock" (French: La Petite Roche) by the French explorer Jean-Baptiste Bénard de la Harpe in the 1720s. The capital of the Arkansas Territory was moved to Little Rock from Arkansas Post in 1821. The city's population was 197,881 in 2018 according to the United States Census Bureau. The six-county Little Rock-North Little Rock-Conway, AR Metropolitan Statistical Area (MSA) is ranked 78th in terms of population in the United States with 738,344 residents according to the 2017 estimate by the United States Census Bureau.