Jefferson Township occupies a large, wooded area in northwestern Morris County along the Sussex County line. The municipality includes several lake communities and neighborhoods, among them Lake Hopatcong, Lake Shawnee, Milton, and Oak Ridge. Route 15 is the principal north-south highway, connecting Jefferson with Dover, Sparta, and Interstate 80. The township’s landscape is defined by ridges, forests, reservoirs, wetlands, and extensive open land. Mahlon Dickerson Reservation, Morris County’s largest park, offers trails, camping, and access to some of the county’s highest terrain. Residential development ranges from lakefront homes and compact neighborhood streets to larger rural properties. Local shopping, schools, municipal facilities, and light industrial areas are distributed along the main road corridors. Jefferson borders Rockaway Township, Roxbury, Mount Arlington, Hopatcong, Sparta, and several other Morris and Sussex County communities. Its natural setting and broad land area give it a character that differs sharply from the denser suburbs farther east.