Norwich is a city in New London County, Connecticut, United States. The Yantic, Shetucket, and Quinebaug Rivers flow into the city and form its harbor, from which the Thames River flows south to Long Island Sound. The city is part of the Southeastern Connecticut Planning Region. The population was 40,125 at the 2020 United States Census. The Norwich–New London metropolitan area includes 21 towns and 274,055 people.