Cities—and the organized life they seemed to promise—were the lynchpin of Spanish settlement of the New World. Unlike the Portuguese, who at first set up "feitorias" that were staffed by transient workers rather than residents, the Spanish intended to settle and stay. Following the first landfalls in the Caribbean, the Spanish crown sent out directives to the conquistadors instructing them to found towns, and soon followed up with specifics of desired organization which reflected current Renaissance–inspired ideals of city planning. This royal edict, issued in 1573, was perhaps the most complete and widely disseminated of 16th century town planning ordinances.

The royal instructions on town planning are scrupulously detailed, down to the location of the slaughterhouses. Conquistadors and missionaries took the royal directives seriously. The new towns, carefully laid out as grids arranged around a central plaza, spread like coinage throughout Spanish America. Most towns and cities had church and government buildings on the plaza, varying from the crown's master plan, but emphasizing the centrality of these institutions in "civilized" life. Today, across Spanish America, the plaza–and–grid still remains in the huge cities of Lima and Mexico City as well as in small towns and villages, and examples of the grid planned city can be seen in many of the maps in the Cities section of Vistas, as well as in the 1562 "Foundational plan of San Juan de la Frontera," in the Vistas gallery.

Recently, scholars have turned their attention from the evident success of Spanish American town planning, measured by the ubiquity of the plaza–and–grid plan, to its social costs. They have investigated the disruptions in communities, particularly indigenous ones, as they were forced onto the plaza–and–grid, and they have also seen how communities modified the strict ordinances to accommodate their particular needs.

See a map of a grid-plan town in the Vistas Gallery.