This article examines the principles underlying Spanish American mail during the government of the first Hapsburgs. I propose that this mail system, in which official and unofficial postal services coexisted, allowed for an intense communicational experience; rather than restricting correspondence, mail circulated at unprecedented levels. To understand this system's rationale I focus on the figure of the correos mayores, who were responsible for the distribution of official information (or information of interest to the crown) within certain Spanish American cities. Using sources in American and European archives, I question the premise that Spanish American communication was chaotic during this period. I also argue that the exceptional circulation of mail within Spanish America and overseas during the sixteenth century is essential for understanding European expansion and the early modern world.