This research analyzes the factors and scope of residential colonization of rural space in the province of Chacabuco, Metropolitan Region of Santiago, Chile, between 1980 and 2020. To this end, it recognizes dynamics associated with the commodification of land and water, the historical and legal background of the dictatorship of Augusto Pinochet, and the limited state control and planning in the real estate business since the 1990s. The methodology combines qualitative and quantitative techniques, including documentary review, satellite image analysis, and building classification. The results show that urbanization processes in the Chacabuco countryside have led to a decrease in arable land, changes in rural practices, a deficit in the provision of infrastructure and (public) services, and more significant fragmentation and socio-spatial segregation. The research reveals that residential colonization in Chacabuco has significantly transformed rural areas over the last four decades, creating tension between competing interests and uncontrolled, market-driven expansion. The role of the State as a deregulator and the lack of planning have exacerbated the situation. Improvements in land use planning are proposed, including greater regional autonomy, data updating, and protection of peri-urban areas.