[23] Rahway and the surrounding area were once the home of the Lenape Native Americans, and tradition states that the city was named after Rahwack (or Ra-wa-rah), a local tribal chief.

The early settlers of Elizabethtown and Woodbridge were the founders of Rahway which began as outlying acreage and plantations.

[28] Rahway saw action during the American Revolutionary War because of its proximity to Staten Island, Elizabethtown and Perth Amboy.

The earliest buildings at the site date to 1795 and the property remains one of Rahway's most prominent historical landmarks.

[33] George Washington visited Rahway during his travel to New York City prior to his presidential inauguration in 1789.

A marker across the street from the tavern reads:[34] Following the Revolution, Rahway became the home of the first national mint to create a coin bearing the inscription E pluribus unum.

[36] Rahway grew due to its location along the major stagecoach and railroad lines between New York City and Philadelphia, Pennsylvania.

[40] The city became home to dozens of major manufacturers, including the Regina Music Box Company, Wheatena, Mershon Bros. and, most importantly, Merck & Co., which was established in Rahway in 1903, when George W. Merck moved his small chemical company to Rahway from New York City.

[41] The national decline in industry after World War II led to the closure of most of Rahway's major manufacturing facilities (except for Merck) and a general deterioration of the city's central business district.

[42] Beginning in the late 1990s, the city launched a plan to revitalize the downtown area and authorized the construction of hundreds of new market-rate housing units, a hotel, art galleries and additional retail space.

The river leaves Rahway at the city limits of Linden and Woodbridge before flowing into the Arthur Kill.

[48] Unincorporated communities, localities and place names located partially or completely within the city include Inman Heights and North Rahway.

"[61]In 2019, the Watt Hotel opened across from the train station, with 100 rooms managed by Hilton on the third and fourth floors of a 17-story building, a lobby cocktail lounge and a rooftop terrace with a seasonal bar offering views of the city, river and outwards to the Watchung Mountains.

As part of the expansion, the facility was purchased by the County of Union for $1.3 million and leased back for $1 a year.

[82] The landmarked Rahway Theatre building is home to the Union County Performing Arts Center.

The best-known is Rahway River Park, which is maintained by Union County, and is also partially located in Clark.

The Robinson's Branch Reservoir abuts the city at the Madison Hill Bridge on the Clark-Rahway border.

The Walter E. Ulrich swimming pool in Rahway River Park was extensively renovated and retiled in 2021.

A beach-style splash feature for children, with an "ocean-like" sloping entry without stairs, was added to the pool that year.

This form of government gives citizens a centralized line of authority for the efficient management of the city's business.

[2] As of 2024[update], the mayor of Rahway is Democrat Raymond A. Giacobbe Jr., whose term of office ends December 31, 2026.

[106][107][108] For the 119th United States Congress, New Jersey's 7th congressional district is represented by Thomas Kean Jr. (R, Westfield).

[110] For the 2024-2025 session, the 22nd legislative district of the New Jersey Legislature is represented in the State Senate by Nicholas Scutari (D, Linden) and in the General Assembly by Linda S. Carter (D, Plainfield) and James J. Kennedy (D, Rahway).

[112] As of 2025[update], Union County's County Commissioners are: Rebecca Williams (D, Plainfield, 2025),[113] Joesph Bodek (D, Linden, 2026),[114] James E. Baker Jr. (D, Rahway, 2027),[115] Michele Delisfort (D, Union Township, 2026),[116] Sergio Granados (D, Elizabeth, 2025),[117] Bette Jane Kowalski (D, Cranford, 2025),[118] Vice Chair Lourdes M. Leon (D, Elizabeth, 2026),[119] Alexander Mirabella (D, Fanwood, 2027)[120] and Chair Kimberly Palmieri-Mouded (D, Westfield, 2027).

[121][122] Constitutional officers elected on a countywide basis are: Clerk Joanne Rajoppi (D, Union Township, 2025),[123][124] Sheriff Peter Corvelli (D, Kenilworth, 2026)[125][126] and Surrogate Christopher E. Hudak (D, Clark, 2027).

[129] Among the city's 2010 Census population, 57.5% (vs. 53.3% in Union County) were registered to vote, including 73.5% of those ages 18 and over (vs. 70.6% countywide).

According to recently resurfaced 19th century lore, Captain William Kidd buried treasure in the Rahway area, alongside the body of one of his men he had just murdered.

The murder and burial of treasure was witnessed secretly from a tree, allegedly, by a Lenape chieftain known as Ra-wa-rah who is the namesake of the city of Rahway.

[156] East Jersey State Prison is seen at the beginning of the movie Ocean's Eleven, starring George Clooney.

[167] The climate in this area is characterized by hot, humid summers and generally mild to cool winters.