In Brazil, the ruins of the São Miguel Arcanjo church constitute the most intact and complete structure among this period’s designated heritage properties. On the Argentinean side, three out of the four Missions (Santa Ana, Loreto, and Santa María) have either maintained their original rural configuration or have been subject to minor modifications. In the Brazilian case, a full reading and understanding into the spatial configuration of São Miguel Arcanjo is provided in a set of surviving documents. The four properties were also declared Historic Cultural Heritage with the enactment of Provincial Law 1280 of 1983. Measures will be adopted over the medium and long terms to ensure proper conservation of the components of the World Heritage property.