High Quality Content by WIKIPEDIA articles! Gastonia is the largest city and county seat of Gaston County, North Carolina, United States. It is also the third largest suburb of the Charlotte Area, behind Concord and Rock Hill. The population was 71,226 as of July 2011 (35% of the population of Gaston County, but as of the Census of 2010 the population was 69,994. Gastonia is the 13th largest city in North Carolina. It is part of the Charlotte metropolitan area, officially designated the Charlotte-Concord-Rock Hill Metropolitan Statistical Area (MSA). Gastonia has experienced steady growth, with a population increase between 2000 and 2010 (according the US Census Bureau) of nearly 8.2%.