Caldwell was incorporated as a borough by an Act of the New Jersey Legislature on February 10, 1892, from portions of Caldwell Township (now Fairfield Township), based on the results of a referendum held on the previous day. In 1981, the name was changed to the "Township of the Borough of Caldwell" to take advantage of federal revenue sharing policies. Effective January 26, 1995, it again became a borough.
Grover Cleveland, the 22nd and 24th President of the United States, and the only president to serve two non-consecutive terms, was born in Caldwell on March 18, 1837. His father, Rev. Richard Cleveland, was pastor of the First Presbyterian Church. The Grover Cleveland birthplace — the church's former rectory — is now a museum and is open to the public.
Though today the Caldwell area is considered to be a suburb of both Newark and New York City, the area originally developed as its own individual, self-contained town and economy rather than as urban sprawl from a larger city. When it was formed, a few miles of woods separated downtown Caldwell from Newark or any of its developing suburbs.
New Jersey Monthly magazine ranked Caldwell as its 32nd best place to live in its 2008 rankings of the "Best Places To Live" in New Jersey.
Caldwell is part of "The Caldwells", the group of three Essex County municipalities which all have the word Caldwell in their name, together with North Caldwell and West Caldwell. All of these communities are named after the Reverend James Caldwell, a Patriot who played an active role supporting the Continental Army during the American Revolutionary War, most notably his actions at the Battle of Springfield, where he gave the soldiers pages from hymn books to use as wadding for their rifle bullets. While each community has its own independent government, and the three municipalities have no shared governance (other than Essex County), the term is often used to refer to the area, including on highway exit signs. Signage for Exit 47B and 52 on Interstate 80 refer to "The Caldwells" as a destination.
There were 3,311 households out of which 23.0% had children under the age of 18 living with them, 42.5% were married couples living together, 9.8% had a female householder with no husband present, and 45.2% were non-families. 38.0% of all households were made up of individuals and 15.4% had someone living alone who was 65 years of age or older. The average household size was 2.17 and the average family size was 2.93.
In the borough the population was spread out with 18.1% under the age of 18, 8.9% from 18 to 24, 32.9% from 25 to 44, 22.3% from 45 to 64, and 17.8% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 82.3 males. For every 100 females age 18 and over, there were 78.6 males.
The median income for a household in the borough was $61,250, and the median income for a family was $81,989. Males had a median income of $53,548 versus $40,543 for females. The per capita income for the borough was $34,630. About 2.5% of families and 4.8% of the population were below the poverty line, including 2.0% of those under age 18 and 7.6% of those age 65 or over.
The Mayor of Caldwell is Susan H. Gartland. Members of the Borough Council are Council President E. William Edge, Jeffrey Curley, Ann Dassing, James Gates, Peter Mescia, and Kay Slattery.
Caldwell and West Caldwell share a great deal of services, including the Recreation Department and the school system. The Board of Recreation Commissioners of the Boroughs of Caldwell and West Caldwell was established in 1947.
There are a number of alternatives for students living in the Caldwell-West Caldwell school district. Private schools in Caldwell include Trinity Academy for kindergarten through eighth grade and Mount Saint Dominic Academy for grades 9-12. Additionally, the Essex County Vocational High School is available for regional students who do not wish to attend their public high schools or who wish to learn a trade.
The Horse Neck Tract consisted of modern day Caldwell, West Caldwell, North Caldwell, Fairfield, Verona, Cedar Grove, Essex Fells, Roseland, and portions of Livingston and West Orange. This land was part of the larger purchase and referred to as the Horse Neck Tract until February 17, 1787, when the town congregation voted to change the name to Caldwell, in honor of the Reverend James Caldwell who pushed for their organization’s creation.
Caldwell Township contained what is today the towns of West Caldwell and Caldwell. Soon after, the area of Caldwell Township just to the east of Caldwell Borough between Caldwell Borough and Montclair (present-day Verona and Cedar Grove) decided to follow Caldwell's lead and incorporated itself as its own borough, Verona. Some of the already-developed eastern neighborhoods of Caldwell Township chose to become part of Montclair, as it was a rapidly-developing suburb of Newark and Paterson. At around the same time, the area north of Caldwell Borough became its own town, North Caldwell. The wooded area directly to the south of downtown Caldwell Borough became Essex Fells. Meanwhile, the farmland to the south of the western portion of Caldwell township attempted to become its own municipality known as South Caldwell. This failed, as much of developed sections of that area lied on its southernmost and easternmost borders, along the expanding Newark suburbs of Livingston and West Orange respectively. Those areas were engulfed by those two towns once they became incorporated municipalities of several small villages and developments.
This left only the most rural farmland south of Caldwell Borough and Essex Fells to become its own township, Roseland. At this point, all that remained of the original Caldwell Township was a large piece of undeveloped land in the northwestern-most part of Essex County; eventually, in the early 1950s, Caldwell Township changed its name to Fairfield in order to avoid being confused with Caldwell Borough.
Immediately following the separation of the original Caldwell, the western part of Caldwell Borough generally remained less developed than downtown Caldwell Borough and contained several farms and a large area of undeveloped swampland known as Hatfield Swamp. However, two individual settlements, known as Franklin and Westville, soon formed in the western part of Caldwell Borough. As development increased and population grew in the western part of Caldwell, the town's more rural western population and more urban east often could not reconcile their differences. This led to the areas of Franklin and Westville consolidating into their own township known as West Caldwell in 1904, leaving only the one square mile of original downtown Horseneck development as the borough of Caldwell. Lewis G. Lockward was elected the first mayor of Caldwell. In 1929, a failed attempt to consolidate the three Caldwells was rejected by voters.