The county was established in 1753 from portions of Morris County and named after the county of Sussex in England. See more

Around 450 million years ago, the Martinsburg Shale was uplifted when a chain of volcanic islands collided with proto North America. These islands slid over the North American plate, and deposited rock on top of the plate, forming the Highlands and … See more

2020 census
2010 census
The 2010 United States census counted 149,265 people, 54,752 households, and 40,626 families in the … See more

County government
Sussex County is governed by the Sussex County Board of County Commissioners whose five members … See more

The area of Sussex County and its surrounding region was occupied for approximately 8,000-13,000 years by succeeding cultures of indigenous peoples. The Munsee Indians inhabited the region at the time of European encounter. The Munsee were a … See more

According to the U.S. Census Bureau, as of the 2020 Census, the county had a total area of 535.54 square miles (1,387.0 km ), of which 518.66 square miles (1,343.3 km ) was land (96.8%) … See more

The Bureau of Economic Analysis calculated that the county's gross domestic product was $4.6 billion in 2021, which was ranked 20th in the state and was a 3.9% increase … See more