New Jersey Route 101 was planned to begin at Harrison Avenue in Kearny, Hudson County. From here, the route was to head north into the New Jersey Meadowlands in Bergen County, where it would pass through Lyndhurst, Rutherford, and East Rutherford. Route 101 would continue north through Carlstadt before running in between Moonachie Road and the Hackensack River. The route was to pass through Little Ferry and into the eastern part of Hackensack, where Route 101 was to terminate at an intersection with Route 4. From this point, Route S101 was planned to continue north to the New York border in Montvale. Route 101
South Brunswick, New Jersey branches, the New York division of the Pennsylvania Railroad, the Rocky Hill and the Jamesburg and Freehold. The Lawrence Brook, a tributary of the Raritan River, flows through the township. Pigeon Swamp State Park is a New Jersey state park located on Deans Rhode Hall Road (Middlesex CR-610). The park has of undeveloped land. The township borders Cranbury Township, East Brunswick Township, Monroe Township, North Brunswick Township and Plainsboro Township in Middlesex County; Princeton in Mercer County; and Franklin Township in Somerset County. South Brunswick is in the humid continental climate zone. Average Winter-time high temperatures range from , and