In 1801, the Straight Turnpike which is now known as Route 1 was constructed. 1872 was a landmark year in History. A separate township of Cranbury was created from the southern extension of South Brunswick reducing the size of the town. In 1919, Plainsboro was created from South Brunswick, further reducing the size. In early South Brunswick history Kingston was an important place of trade and commerce. It lay on King's Road and Milestone River making it a favorable spot for traders to start business.

Another important place was Dayton, named after William L. Dayton, an attorney for the Freehold and Jamesburg Agricultural Railroad. In the middle of the 18th century Dayton had a tavern and a brick manufacturing unit. Much of the development in South Brunswick happened in the 20th century. In 1900, the fast line between New Brunswick and Trenton became operational. In 1951, the New Jersey Turnpike became operational on the Eastern side of South Brunswick. The Turnpike turned New Brunswick from a primarily agricultural township to an industrial area.

Kendall Park, located off Route 27 was the first major suburban type development in South Brunswick NJ. Today the town has approximately 33, 400 residents. Though the town has seen much development still many areas of the 42 square miles of the township are underdeveloped.