Monroe is the largest city and county seat of Monroe County in the U.S. state of Michigan. Monroe had a population of 20,462 in the 2020 census. The city is bordered on the south by Monroe Charter Township, but the two are administered autonomously. Monroe is the core city in the Monroe metropolitan statistical area, which is coterminous with Monroe County and had a population of 154,809 in 2020. Located on the western shores of Lake Erie approximately 14 miles (23 km) north of Toledo, Ohio and 25 miles (40 km) south of Detroit, the city is part of the Detroit–Ann Arbor–Flint combined statistical area.