This proto-industrial complex, while exceptional, came under serious threat in the 1950s and 1960s. In addition to the absence of a vocation and use, many issues complicated the safeguarding and reclassification of this unique site.

Several buildings and works had to be demolished due of a lack of “safety, their state of deterioration, or their lack of historical value” (Beaudet, 2017: 162). In the 1960s, Île-des-Moulins even became the site of a trailer park. Given the condition of the buildings and the fact that the owner at the time did not want any public intervention on the site, the Ministère des Affaires culturelles acquired the island in order to reclassify it.

However, after its acquisition, other obstacles slowed the progress of the project: the owners of Île Saint-Jean opposed the construction of a footbridge between the two islands, the costs related to the initial project ballooned and there was a public finance crisis. This explains why the reclassification of Île-des-Moulins took some 20 years to complete.

The historical restoration of Île-des-Moulins is the second project of this nature to have been undertaken, along with the restoration of Place-Royale in Quebec City. In both instances, a similar approach was employed. The reference period used as the basis for the project was 1832 to 1883, to coincide with Masson’s era, considered the peak period for the site. The project entailed restoring the mills and the seigneurial office with an eye to creating a public urban cultural park.

Citizen action led to the reclassification of the mills along the road. Terrebonne’s municipal library was to be built close to Île-des-Moulins, at the very time that the mills were in need of a new vocation. Citizens proposed to the Ministère des Affaires culturelles that the library be opened in the mills and to reallocate the funds that had been earmarked for the construction of the library to the restoration of the building, which the Ministère agreed to do.

Lastly, in addition to being converted into an urban cultural park, recognition of the first vocation of Île-des-Moulins took on greater importance over the years, to mark the significance of this proto-industrial site in the development of the region and the province.

The players in this reclassification process included the Ministère des Affaires culturelles, which classified the site and purchased it in order to launch the necessary rehabilitation work, and the City of Terrebonne, which in turn purchased the site from the Ministère des Affaires culturelles to consolidate its use as an urban cultural park as well as to further develop the site through the consolidation of its built and landscape heritage, highlighting its architectural and natural features.

While most industrial complexes on the territory tend to be cut off from the surrounding area, Île-des-Moulins adjoins Old Terrebonne. It has had a significant influence on the development of this sector thanks to the direct connection between the two sites and their complementarity. This synergy was taken into account during the reclassification process. While Old Terrebonne has mixed contemporary interventions with conventional preservation approaches since the 1980s, the development of these two territories was nevertheless a gamble that paid off.