Gaston County is a county in the U.S. state of North Carolina. As of the 2020 census, the population was 227,943. The county seat is Gastonia. Dallas served as the original county seat from 1846 until 1911.

Gastonia is the most populous city in and county seat of Gaston County, North Carolina, United States. It is the second-largest satellite city of the Charlotte area, behind Concord. The population was 80,411 in the 2020 census, up from 71,741 in 2010. Gastonia is the 13th-most populous city in North Carolina. It is part of the Charlotte-Concord-Gastonia, NC-SC Metropolitan Statistical Area, which is part of the Charlotte-Concord, NC-SC Combined Statistical Area.