In conclusion, our work suggests that the 2009 A/H1N1 influenza pandemic in Peru exhibited a rich spatial-temporal pattern with two pandemic waves of A/H1N1 cases of varying timing and impact across age groups and geographic regions. Larger population areas experienced earlier pandemic onset, suggesting a hierarchical influenza transmission pattern reminiscent of past influenza epidemics and pandemics. Overall, our findings suggest that population size, population density, and school activity periods can account for some of the observed variability in influenza pandemic patterns.