By mid-March 2020, the COVID-19 pandemic spread to over 100 countries and all 50 states in the US. Government efforts to minimize the spread of disease emphasized behavioral interventions, including raising awareness of the disease and encouraging protective behaviors such as social distancing and hand washing, and seeking medical attention if experiencing symptoms. However, it is unclear to what extent individuals are aware of the risks associated with the disease, how they are altering their behavior, factors which could influence the spread of the virus to vulnerable populations. We characterized risk perception and engagement in preventative measures in 1591 United States based individuals over the first week of the pandemic (March 11th-16th 2020) and examined the extent to which protective behaviors are predicted by individuals’ perception of risk. Over 5 days, subjects demonstrated growing awareness of the risk posed by the virus, and largely reported engaging in protective behaviors with increasing frequency. However, they underestimated their personal risk of infection relative to the average person in the country. We found that engagement in social distancing and handwashing was most strongly predicted by the perceived likelihood of personally being infected, rather than likelihood of transmission or severity of potential transmitted infections. However, substantial variability emerged among individuals, and using data-driven methods we found a subgroup of subjects who are largely disengaged, unaware, and not practicing protective behaviors. Our results have implications for our understanding of how risk perception and protective behaviors can facilitate early interventions during large-scale pandemics.