Participatory mapping acts as a foundational tool that enables the reclamation and redefinition of urban commons. By allowing communities to visualize and collaborate on their spatial knowledge, participatory mapping empowers residents to identify under-utilized land, neglected infrastructure, or ecologically degraded areas with potential for reclamation. In many cases, these mapping efforts serve as the first step toward reimagining such spaces as urban commons and becoming collectively governed and regenerated assets for community use. For instance, former industrial zones or informal settlements, once mapped and made visible through community-led efforts, can become sites for cooperative housing, public green space, or public transit systems. Similarly, mapping practices can reveal historically excluded groups and invisible boundaries, helping to democratize decision-making during the repurposing of land. In this way, participatory mapping is not only a representational act but also a political one: it challenges dominant narratives of land ownership and usage, promotes equitable access, and directly supports the practices of self-organization and place-making that underpin both urban commons and land reclamation. As cities strive to address climate resilience, social equity, and spatial justice, the integration of participatory mapping into urban planning processes becomes a strategic method for enabling bottom-up reclamation and co-managed public space.