“Rugged individualism”—the combination of individualism and anti-statism—is a prominent feature of American culture with deep roots in the country’s history of frontier settlement. Today, rugged individualism is more prevalent in counties with greater total frontier experience (TFE) during the era of westward expansion. While individualism may be conducive to innovation, it can also undermine collective action, with potentially adverse social consequences. We argue that America’s frontier culture hampered responses to the COVID-19 pandemic. Across U.S. counties, greater TFE is associated with less social distancing and mask use as well as weaker local government effort to control the virus. We argue that frontier culture lies at the root of several more proximate explanations for the weak collective response to public health risks, including a lack of civic duty, partisanship, and distrust in science.