4) The remains of an ancient cemetery dating back to the 18th century.

The 2002–2003 archaeological excavations uncovered the remains of an 18th century cemetery. After 120 years of use, this former cemetery contained about 7,000 bodies. In 1840, the land was bought to serve as a cemetery on what is now the parking lot and the city hall; it is moved again in 1886, onto Montée Masson.

The building of the Theatre du Vieux-Terrebonne covers the land where 141 bodies were buried. The remains were moved before work could resume. They were buried again at the regional cemetery (Chemin Martin), where a monument was raised in their memory.