Texarkana is the largest city and the county seat of Miller County, Arkansas, United States. Texarkana is a twin city with Texarkana, Texas, along State Line Avenue.According to the 2016 census, the population of the city was 30,283, ranking it as the state's 12th largest city, behind Hot Springs. The city, along with its Texas counterpart, forms the central city of the Metropolitan Statistical Area, encompassing all of Bowie County, Texas, and Miller County, Arkansas. The combined population of the two Texarkana cities was 66,330 at the 2010 census.