tarrant_county,_texas | countyseat | fort_worth,_texas <tsp> texas | capital | austin,_texas <tsp> arlington,_texas | ispartof | tarrant_county,_texas <tsp> arlington,_texas | ispartof | texas <tsp> texas | largestcity | houston <sep> tarrant county is located in the us state of texas as of 2020, it had a population of 2,110,640 it is texas' third-most populous county and the 15th-most populous in the united states its county seat is fort worth 
houston is the largest city in texas where arlington is located in tarrant county. the county seat is fort worth and the state capital is austin.tarrant county texas texas is the third-most populous county in the united states