The Union Fire Club of Salem, Massachusetts, was founded in 1748. In 1749, members petitioned the Salem Town Meeting to buy a fire engine and form a company to run it; in return they were to be excused from town duties, such as jury duty. The engine was received in 1749 and was named the Union. Like other early fire engines, the Union was horse-drawn and had no suction; it had to be filled from buckets. That engine is now the collection of the Peabody Essex Museum, as well as an oil painting of it, entitled "The Union Hand-Tub," by W. B Eaton (1836-1890).

A second engine was received in 1750 and remained in use until 179[7], when a third engine named the Essex, was purchased. At this period in time the company was known as the Union and Essex Engine Company. In 1827, a hose carriage and hose were attached to the engines and as a consequence new members were added.

In 1832, the town of Salem proposed construction of a building at the corner of Court and Forrester streets to house this engine company, along with the Sail Company and the Hook & Ladder Company. In 1834, the structure, known as the Hall, was completed, and the building was rented to Miss Cross's Primary School for Girls, with the provision that the companies would use the Hall for evening meetings and at other times "which should not interfere with the School." (In 1857 the company petitioned the Salem Board of Engineers that Sail Carriage No. 2 be removed from the building because of lack of space and the dissolution of the company which operated it.)

In September 1836, the company petitioned the City Council for a new engine "of equal power with the other Engines of the city." On September 23, 1837, the Chief Engineer of the Salem Fire Department reported that the City Council had authorized an expenditure of $750 to purchase an engine and fixtures from Hunneman, Thayer and Hill of Roxbury. The engine was received on October 11th and was named the Naumkeag; the company changed its name that day to the Union and Naumkeag Engine Company. In July 1844, the Salem City Council denied a petition of "a portion of the Fire Department" that fireman should receive additional compensation, and a number of firefighters from other companies resigned. A special meeting of the Union and Naumkeag Engine Company unanimously passed a resolution that "Although a considerable portion of our Company are in favour of a further compensation we as good citizens and members of the Fire Department pledge ourselves to an active and faithful performance of the duties of Firemen…."

In addition to responding to fires, the company held regular meetings and holiday celebrations, including parades. A ball was held to commemorate the company's 106th anniversary, in 1854, and there were other anniversary celebrations in 1855 and 1858.

The company claimed to own the oldest engine in the United States and to be the oldest engine company in the country that could show an uninterrupted existence. It was disbanded in 1861, after the introduction of steam fire engines. The membership roster lists a total of 557 members, from 1748 to 1861.