This paper was revised on June 18, 2020
On April 7, 2020, Wisconsin held a major election for state positions and presidential preferences for both major parties. News reports showed pictures of long lines of voters due to fewer polling locations and suggested that the election may further the spread of the SARS-CoV-2 virus. A contact-tracing analysis by the Wisconsin Department of Health Services identified 71 confirmed cases of COVID-19 to in-person voting, but no research has conducted a broader analysis of the extent to which in-person voting increased the number of COVID-19 cases. We use county level data on voting and COVID-19 tests to connect the election to the spread of the SARS-CoV-2 virus. We find a statistically and economically significant association between in-person voting and the spread of COVID-19 two to three weeks after the election. Results indicate that on average a 10% difference in in-person voters per polling location between counties is associated with approximately a 17.7% increase in the positive test rate. Further, extrapolation of estimates from the average county suggests that in-person voting was related to approximately 700 more COVID-19 cases in Wisconsin during the weeks following the election, or about 7.7% of the total number of confirmed cases during the five week post-treatment time period studied.