benton_county,_oregon | largestcity | corvallis,_oregon <sep> benton county is one of the 36 counties in the us state of oregon as of the 2020 census, the population was 95,184 its county seat is corvallis the county was named after thomas hart benton, a us 
the largest city in benton county. oregon. is corvallis. oregon.corvallis oregon is the county seat of benton county