This dissertation interrogates postcolonial cities’ syncretic territories, using Huế’s mnemonic sites – historically and culturally significant locales that aid in remembrance – to explore displaced communities’ cohabitation tactics and decolonization efforts. As Vietnam’s former imperial capital with a multifaceted history, from a Vietnamese settler colony to a French protectorate, Huế offers a unique milieu to investigate how everyday place-making and preservation negotiate with nationalism and heritagization – contemporary valorization of historical elements. The city represents the tensions between rapid urbanization, heritage preservation, postcolonial identity construction, and urban realities. This research, situated at the nexus of urbanism and heritage studies, critiques dichotomies in the postcolonial setting, such as East-West, colonized-colonizer, nature-culture, and tangible-intangible. By introducing “Impromptu Conservation,” this study re-evaluates UNESCO heritage paradigms. It champions a grassroots, community-driven conservation approach that challenges the prevalent top-down, retrospective, and often costly strategies prioritizing discrete monuments and urban master plans that might fragment the fabric. This viewpoint recasts “heritage,” transcending the restrictive confines of the Authorized Heritage Discourse (Smith 2006), and centers dwelling as an ongoing conservation practice. In Huế, the dominant narrative surrounding the Nguyễn dynasty, especially after UNESCO recognition, has overshadowed other significant historical actors. This research unveils the local populace’s aspirations and migrant place-making tactics and the postcolonial dynamics’ intricacies. Drawing from Walter Benjamin’s montage method and the architectural and urban typo-morphology analyses, the dissertation confronts the marginalization of Huế’s mnemonic sites, often sidelined by historicist labels that deem them regressive. These views, once used to justify colonization, now facilitate post-independence nations’ selective historicization and simultaneous disavowal of their past, oversimplifying historical accounts and silencing subordinate voices. This study integrates fieldwork (site visits and interviews) with archival research (colonial, imperial, and village sources) to illuminate locals’ inhabitation deeply embedded in the Huong River’s basin. Their everyday practices strengthen communal ties and foster the “impromptu conservation” of collective memories despite political shifts. By traversing spatial scales, temporal scopes, and knowledge hierarchy, the research transcends boundaries in knowledge production to reclaim local skills and know-how while freeing conservation from power imbalances, authoritative impositions, or financial constraints. The dissertation starts with a prologue, followed by an extensive literature review on postcolonial cities and heritage discourse. It then introduces and applies a site-based montage methodology inspired by interdisciplinary theoretical frameworks to examine Huế’s multi-scalar mnemonic sites. It concludes with an epilogue expanding on “Impromptu Conservation,” suggesting further theorization and potential applications in urbanism and heritage spheres. This research enhances urbanism’s socio-cultural and historical dimensions. It underscores the importance of place and space in heritage studies, pushing for a grounded, territorial turn in both fields, especially within postcolonial contexts.