Bound Brook is a borough in Somerset County, New Jersey, United States, located along the Raritan River. At the 2010 United States Census, the borough's population was 10,402, reflecting an increase of 247 from the 10,155 counted in the 2000 Census, which had in turn increased by 668 from the 9,487 counted in the 1990 Census.Bound Brook was originally incorporated as a town by an act of the New Jersey Legislature on March 24, 1869, within portions of Bridgewater Township. On February 11, 1891, it was reincorporated as a borough, based on the results of a referendum held on the previous day.