This directed case study is intended to give students insight into why social distancing is used to minimize the spread of infectious diseases. Students are provided with data from the state of Washington to determine whether there is a trend in transmission rates of COVID-19 in large populations and if population density is a driving force in disease spread. Students analyze population data, number of cases, and population density of ten counties. They also view the timeline of social distancing measures announced in the state, determine when the social distancing recommendation began, and observe how quickly the number of cases escalated. Students then compare Washington state data with New York state data to see how much quicker COVID-19 cases escalated in New York and how much faster social distancing measures were put into place. Students then turn their attention to Colorado to observe the exponential growth trend witnessed there. This case was designed for high school biology and AP biology students but could also be used in other courses that require students to analyze data. The case uses data as of March 2020, but could easily be updated with new data as the situation continues to develop.