Sussex County is a county located in the southern part of the U.S. state of Delaware. As of the 2010 census, its population was 197,145, an increase of 25.9% over the previous decade. The county seat is Georgetown. The Seaford Micropolitan Statistical Area, which is the largest micropolitan area in the United States, includes all of Sussex County.
Sussex County is Delaware's largest county by land area, with 938 square miles (2,429 km2). The first European (Dutch) settlement in the state of Delaware was founded in 1631 near the present-day town of Lewes. However, Sussex County was not organized until 1683.