When the novel strain of A/H1N1 influenza first appeared in spring 2009, closing schools was initially a common and often challenging strategy implemented in many communities. Arguments for and against closing schools are likely to arise anew if influenza spikes in the fall of 2009. Policymakers and community officials considering this and other nonpharmaceutical responses can learn from the experiences of ninety-one years ago, during the 1918-19 influenza pandemic that killed thousands of Americans. Analysis of the school closure policies of forty-three U.S. cities during that pandemic shows that smooth implementation was associated with clear lines of authority among agencies and with transparent communication between health officials and the public.