Erie County is a county in the Commonwealth of Pennsylvania. It is the northernmost county in Pennsylvania. As of the 2020 census, the population was 270,876. Its county seat is Erie. The county was created in 1800 and later organized in 1803. The county is part of the Northwest Pennsylvania region of the state.

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 (130 km) from Buffalo, 90 miles (140 km) from Cleveland, and 120 miles (190 km) from Pittsburgh.