This article analyzes the transformations of the southern border of the ancient Tenochtitlan Island in terms of spatiality and collective liminality zones in pre-hispanic times when these changes were oriented toward new territorial modalities and institutional border determination. These characteristics defined the Republic of Indians that was settled amidst the viceroy territory (Mexico City) from the 16th century. Collection and systematization of a broad range of archive, document, and bibliographic sources resulted in the taxonomic change of the administration status for four southern population centers with conurbation characteristics: Toltenco, Zoquipan, Mixiuhcan and Iztacalco. The conjunction among tax interests of the elite indigenous members of the city Cabildo, the overcoming of ecological catastrophes, and the political agency offered by the Saint Francis Order.