The town is named after a "long ford" (from the Latin longa guada) that allowed crossing of the Chiers in Roman times.
It was known as
Longagio (634),  Longio (973), Longione (973), monasterri longagionis (10th century), Longion (1030), Longuion (1209), Longuio (1756).

Several Gallo-Roman sites were excavated in 1934 containing the remains of substructures and fragments of painted plaster.
A necropolis of the later Roman Empire was excavated in 1843 in Magé.

The first mention of Longuyon (as Longagio) dates from 634.
At that time there is already a chapel dedicated to Saint Agatha, which became a collegiate church in 1120, and later served as a barracks for French soldiers in 1636.

The castle of Mussy, first mentioned in 1144, was razed in 1670 by the French occupation troops by order of Louis XIV.

Longuyon was a capital of the Bailiwick of Longuyon from June 1751 to 1789, then the capital of the Canton of Longuyon until March 2015.

In 1914 the town had 2,300 inhabitants.
It was devastated on August 23–24 of that year by the Prussian infantry and 86 inhabitants, men, women, and children, were executed by firing squad.

Longuyon has long been an important railroad crossroads, located between the iron ore of the Briey basin and the coal mining area of the North.

The apartment blocks on the southwestern edge of town, still called "La Cité Canadienne", were home to Royal Canadian Air Force staff and their families in the 1950s and 1960s, when the RCAF had an airbase at nearby Marville.
The street names still carry the names Toronto, Montreal, etc.,
and a totem pole was erected as a monument to the Canadian presence in Longuyon.
The town is named after a "long ford" (from the Latin longa guada) that allowed crossing of the Chiers in Roman times. It was known as
Longagio (634),  Longio (973), Longione (973), monasterri longagionis (10th century), Longion (1030), Longuion (1209), Longuio (1756).
Several Gallo-Roman sites were excavated in 1934 containing the remains of substructures and fragments of painted plaster. A necropolis of the later Roman Empire was excavated in 1843 in Magé.
The first mention of Longuyon (as Longagio) dates from 634. At that time there is already a chapel dedicated to Saint Agatha, which became a collegiate church in 1120, and later served as a barracks for French soldiers in 1636.
The castle of Mussy, first mentioned in 1144, was razed in 1670 by the French occupation troops by order of Louis XIV.
Longuyon was a capital of the Bailiwick of Longuyon from June 1751 to 1789, then the capital of the Canton of Longuyon until March 2015.
In 1914 the town had 2,300 inhabitants. It was devastated on August 23–24 of that year by the Prussian infantry and 86 inhabitants, men, women, and children, were executed by firing squad.
Longuyon has long been an important railroad crossroads, located between the iron ore of the Briey basin and the coal mining area of the North.
The apartment blocks on the southwestern edge of town, still called "La Cité Canadienne", were home to Royal Canadian Air Force staff and their families in the 1950s and 1960s, when the RCAF had an airbase at nearby Marville. The street names still carry the names Toronto, Montreal, etc., and a totem pole was erected as a monument to the Canadian presence in Longuyon.
Longuyon