Suwanee is a city in Gwinnett County and a part of the Atlanta metropolitan area in the U.S. state of Georgia. As of the 2010 census, the population was 15,355; this had grown to an estimated 20,907 as of 2019. In 2020, its population was 20,786. Portions of Forsyth and Fulton counties also have Suwanee and its ZIP code as a mailing address.