Sussex is a borough in northern Sussex County, New Jersey, set in the Skylands region where the Kittatinny Mountains rise west of the Wallkill River valley. With a population of about 2,100, it is a compact, largely residential community that anchors the northern end of Route 23, one of the principal corridors through northwestern New Jersey toward the New York state line at Port Jervis. The borough's setting is decidedly rural. Farmland, forested ridges, and Papakating Creek—a Wallkill River tributary—surround the town, and the broader Sussex County landscape is known for lakes, state parks, and open space. Route 23 runs through the community and was realigned in the early 2010s, with a new bridge over Papakating Creek and a reconfiguration of its northbound and southbound lanes that reshaped the borough's main thoroughfare. Sussex serves as a small local center within the county, but most residents travel to nearby towns such as Newton, the county seat, or to the larger commercial areas of northern New Jersey for work and services. The community's public schools are provided by the Sussex-Wantage Regional School District through eighth grade, with students moving on to High Point Regional High School. Recreation is a defining feature of life here. The Wallkill River National Wildlife Refuge, with its Liberty Loop Trail, lies close by and offers birding and walking, while High Point State Park—home to New Jersey's highest point—and the Appalachian Trail are within a short drive. The borough offers a quiet, outdoors-oriented alternative within commuting reach of the New York metropolitan area for those who value space and natural surroundings. Residents prize the small-town feel and the easy access to hiking, fishing, and open land that the Skylands region provides.