Erie is a city on the south shore of Lake Erie and the county seat of Erie County, Pennsylvania, United States. It is the fifth-most populous cit…Erie is a city on the south shore of Lake Erie and the county seat of Erie County, Pennsylvania, United States. It is the fifth-most populous city in Pennsylvania and the most populous in Northwestern Pennsylvania with a population of 94,831 at the 2020 census. The Erie metropolitan area, equivalent to all of Erie County, had a population of 270,876 in 2020. Erie is located about 80 miles from Buffalo, 90 miles from Cleveland, and 120 miles from Pittsburgh.