The borough had the 20th-highest property tax rate in New Jersey with an equalized rate of 4.442% in 2020, compared to 3.470% in the county as a whole and a statewide average of 2.279%.[20]

Commercial Township was incorporated as a township by an act of the New Jersey Legislature on February 27, 1874, from portions of Downe Township.[19] The township was named for its shellfish industry.[20]

Harrington Park was formed on March 29, 1904, from portions of Harrington Township and Washington Township, and parts of the borough of Closter.[21][22]

The borough of Northvale was formed on March 15, 1916, from the remaining portions of Harrington Township, based on the results of a referendum held on April 4, 1916. With the creation of Northvale, Harrington Township was dissolved. Portions of Northvale were transferred to create the borough of Rockleigh, as of March 13, 1923.[20] The borough’s name derives from its location and topography.[21]

Point Pleasant Beach was incorporated as a borough by an act of the New Jersey Legislature on May 18, 1886, from portions of Brick Township, subject to the results of a referendum passed the previous day.[21]

Alexandria was formed by Royal charter on March 5, 1765, from portions of Bethlehem Township, and was incorporated as one of New Jersey’s initial 104 townships by an act of the New Jersey Legislature on February 21, 1798. Portions of the township were taken to form Frenchtown (April 4, 1867), Holland Township (April 13, 1874, restored to Alexandria on March 4, 1878, and recreated on March 11, 1879) and Milford (April 15, 1911).[19] The township was named for James Alexander, a surveyor who served as New Jersey Attorney General and who had acquired 10,000 acres (4,000 ha) of land in the area in 1744.[20][21]

Delanco was named for the Delaware River and Rancocas Creek, which border the community. It was originally called Del-Ranco or Delaranco, a syllabic abbreviation later shortened to Delanco.[21][22]

Penns Grove had the fourth-highest property tax rate in New Jersey, with an equalized rate of 5.556% in 2020, compared to 3.476% in Salem County and a statewide average of 2.279%.[22]

What is now South Bound Brook was originally formed as a town within Franklin Township. On March 16, 1869, the name of the community was changed to Bloomington, which lasted until May 29, 1891, when the name reverted to South Bound Brook town. South Bound Brook was incorporated as an independent borough by an act of the New Jersey Legislature on April 11, 1907, based on the results of a referendum held on May 1, 1907.[21][22]

Flemington is an independent municipality completely surrounded by Raritan Township and is located near the geographic center of the township.