As COVID-19 spread even faster across the US in 2020, interventions were implemented at the national, state, and even county level. Some of the most integral policies were masking mandates, whose implementation different across states. This study, which features PISC Senior Spatial Analyst Vicky Tam, MA, investigated the association between county-level public masking mandates and daily COVID-19 cases in 394 counties. The authors found that compared to unmasked counties, the daily case incidence per 100,000 people in masked counties declined by 23 percent at four weeks, with the percent decreasing with time. Urban counties and Republican-leaning counties in particular saw increased benefits, with the study declaring that mask mandates provided tangible benefits for its recipients.