In this paper, I study long-run population changes across U.S. metropolitan areas. First, I argue that changes over a long period of time in the geographic distribution of population can be informative about the so-called \resilience» of regions. Using the censuses of population from 1790 to 2010, I find that persistent declines, lasting two decades or more, are somewhat rare among metropolitan areas in U.S. history, though more common recently. Incorporating data on historical factors, I find that metropolitan areas that have experienced extended periods of weak population growth tend to be smaller in population, less industrially diverse, and less educated. These historical correlations inform the construction of a regional resilience index.