Lumberton is a township in Burlington County, in the U.S. state of New Jersey. It is part of the Delaware Valley / Philadelphia metropolitan area. As of the 2020 United States census, the township's popula…Lumberton is a township in Burlington County, in the U.S. state of New Jersey. It is part of the Delaware Valley / Philadelphia metropolitan area. As of the 2020 United States census, the township's population was 12,803, an increase of 244 from the 2010 census count of 12,559, which in turn reflected an increase of 2,098 from the 10,461 counted at the 2000 census.