Petit-Enghien (Dutch: Lettelingen; Walloon: Piti-Inguî) is a town of Wallonia and a district of the municipality of Enghien, located in the province of Hainaut, Belgium.
At the time, the municipality also included the village of Marcq [fr].
As with Enghien, Petit-Enghien was originally Dutch-speaking, but became majority French-speaking mostly through the education system.
Petit-Enghien is near the language border, and as part of Enghien, it is a municipality with language facilities.
Petit-Enghien was the site of Belgian cyclist and multiple Tour de France winner Eddy Merckx's first ever victory on October 1, 1961.