In an observational study of 15 states between April and May of 2020, state community-wide (as opposed to work-specific) mask requirements have prevented 200,000 Covid-19 deaths as compared with states who did not introduce such requirements. This study does control for economic opening, but not mask regulation compliance. Although other studies attempting to measure the effect of contamination on an individual with and without a face mask have been for the most part inconclusive and frustrated by small sizes in studies of a variety of respiratory illnesses. However, this study suggests that, en masse, mask usage is a useful preventative tool.