tarrant_county,_texas | countyseat | fort_worth,_texas <tsp> arlington,_texas | ispartof | tarrant_county,_texas <tsp> arlington,_texas | ispartof | texas <tsp> texas | country | united_states <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 
the state of texas in the us is the location of houston. the largest city. and also arlington. part of tarrant county where fort worth is the county seat.it is texas' third-most populous county and the 15th-most populous in the united states