As of March 23, 2011, there were a total of 4,162 registered voters in Bound Brook, of which 1,149 (27.6% vs. 26.0% countywide) were registered as Democrats, 955 (22.9% vs. 25.7%) were registered as Republicans and 2,050 (49.3% vs. 48.2%) were registered as Unaffiliated. There were 8 voters registered to other parties. Among the borough's 2010 Census population, 40.0% (vs. 60.4% in Somerset County) of the total population were registered to vote, including 51.7% of those ages 18 and over (vs. 80.4% countywide).