Gastonia is the largest city and county seat of Gaston County, North Carolina, United States. It is also the second largest satellite city of the Charlotte area, behind Concord. The population was 71,741 at the 2010 Census. Gastonia is the 13th largest city in North Carolina. It is part of the Charlotte metropolitan area, officially designated the Charlotte Metropolitan Statistical Area (MSA). Gastonia has experienced steady growth, with a population increase between 2000 and 2010 of nearly 8.2%, according to the U.S.