The area that would become the borough had been known as Corona from the mid-1800s and grew up around the two local railroad stations. The name “Hasbrouck” was chosen in 1889 to honor Jacob Dillon Hasbrouck (1842–1918), general manager of the New Jersey and New York Railroad.[21][22] In the face of local opposition, the name change was promoted as improving the community’s public perception and avoiding confusion with the Corona, Queens neighborhood, while “Heights” was added to avoid confusion with a similarly named community in upstate New York.[23]

The borough has been one of the state’s highest-income communities. Based on data from the American Community Survey for 2013–2017, Glen Rock residents had a median household income of $162,443, ranked 6th in the state among municipalities with more than 10,000 residents, more than double the statewide median of $76,475.[21]

As of the 2010 United States Census, the borough’s population was 12,098,[21][22][22][23] reflecting a decline of 325 (-2.6%) from the 12,423 counted in the 2000 Census, which had in turn increased by 791 (+6.8%) from the 11,632 counted in the 1990 Census.[24]

The Freeholds region, which includes the borough and Freehold Township (which completely surrounds the borough), is a commercial hub for central New Jersey. The borough is located relatively close to the Raritan Bayshore communities to the north, such as The Amboys, Old Bridge, Matawan, Keyport, Keansburg, and Middletown, along with being relatively close to the Tri-City region of Jersey Shore municipalities (and their vicinities) to the east, including Red Bank, Long Branch, and Asbury Park.[26]

New Jersey Monthly magazine ranked Upper Township as its 2nd best place to live in its 2008 rankings of the “Best Places To Live” in New Jersey.[19]

Haddonfield was incorporated by an act of the New Jersey Legislature on April 6, 1875, within portions of Haddon Township following a referendum on the same day. The borough became an independent municipality in 1894.[22] The borough was named for Elizabeth Haddon, an early settler of the area.[23][24]

Woolwich was formed by royal charter on March 7, 1767 from portions of Greenwich 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 Franklin Township (January 27, 1820), Spicer Township (March 13, 1844, now known as Harrison Township), West Woolwich Township (March 7, 1877, now known as Logan Township) and Swedesboro (April 9, 1902).[19][20] The township was named for Woolwich, England.[21]

Florham Park was incorporated as a borough by an act of the New Jersey Legislature on March 9, 1899, from portions of Chatham Township.[21][22] In 2012, Forbes.com listed Florham Park as 440th in its listing of “America’s Most Expensive ZIP Codes”, with a median home price of $675,107.[23] According to usa.com, from 2010–2014, the median home price was $612,400.

The township had the 24th-highest property tax rate in New Jersey, with an equalized rate of 4.285% in 2020, compared to 3.476% in the county as a whole and a statewide average of 2.279%.[23]

Oakland was incorporated as a borough by an act of the New Jersey Legislature on April 8, 1902, from portions of Franklin Township (now Wyckoff).[21][22] The name comes from the white oak trees in the area.[23]