In Peru, land invasions have played an informal yet prominent role in implementing agrarian reform. In the southern Andes, peasant mobilization and land takeover were used as a means to circumvent a stalled expropriation process. Strategic lessons learned in agrarian settings have application on the margins of cities as well. New “urban areas” created out of expropriated hacienda lands in Cuzco were initiated by spontaneous occupancy which gradually became regulated and standardized in predictable ways. Administrative planning becomes a response to land takeover, playing a retrospective role in situations in which internal kinds of development already are unfolding. State permissiveness towards illegal occupancy is a carefully courted prize, not to be taken for granted. Nevertheless, residents invest years of effort in building their homes and neighborhoods, in the hope of eventually prevailing, despite contradictory and frustrating experiences with changing policies and bureaucratic encounters.