What is now Barnegat Township was incorporated as Union Township on March 10, 1846, from portions of both Dover Township (now Toms River Township) and Stafford Township, while the area was still part of Monmouth County. It became part of the newly-formed Ocean County on February 15, 1850. Portions of the township were taken to form Lacey Township , Ocean Township , Harvey Cedars and Long Beach Township . Union Township changed its name to Barnegat Township as of January 1, 1977.
Barnegat CDP (2000 Census population of 1,690) is a census-designated place and unincorporated area located within Barnegat Township. Ocean Acres (13,155) is a census-designated place and unincorporated area split between Barnegat Township and Stafford Township.
As of the census of 2000, there were 15,270 people, 5,493 households, and 4,191 families residing in the township. The population density was 440.4 people per square mile (170.1/km²). There were 6,066 housing units at an average density of 175.0/sq mi (67.6/km²). The racial makeup of the township was 94.75% White, 2.21% African American, 0.09% Native American, 1.00% Asian, 0.70% from other races, and 1.25% from two or more races. Hispanic or Latino of any race were 3.86% of the population.
There were 5,493 households out of which 35.3% had children under the age of 18 living with them, 63.0% were married couples living together, 9.7% had a female householder with no husband present, and 23.7% were non-families. 20.2% of all households were made up of individuals and 12.0% had someone living alone who was 65 years of age or older. The average household size was 2.76 and the average family size was 3.19.
In the township the population was spread out with 27.1% under the age of 18, 6.6% from 18 to 24, 26.0% from 25 to 44, 22.4% from 45 to 64, and 17.9% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 93.0 males. For every 100 females age 18 and over, there were 88.6 males.
The median income for a household in the township was $48,572, and the median income for a family was $56,093. Males had a median income of $42,460 versus $28,452 for females. The per capita income for the township was $19,307. About 5.1% of families and 6.2% of the population were below the poverty line, including 9.7% of those under age 18 and 4.9% of those age 65 or over.
In addition to easy access to and from the Garden State Parkway, Barnegat is a hub of major state and county highways. Route 72, which runs east to west, provides access to Burlington County and Philadelphia. County Route 539, which intersects Route 72, links the Township with Trenton. U.S. Route 9 and the Garden State Parkway split the Township east-west.
New Jersey Transit provides bus service to Atlantic City on the 559 bus route.