More than 1.2 million COVID-19 cases have been confirmed in the U.S. as of Thursday afternoon May 7, by far the most of any country. Accounting for population size, the U.S. has the 13th highest number of confirmed COVID-19 cases and the 13th most deaths per capita of any country.

Within the United States, every state is dealing with its own outbreak. New York has by far the most cases and the highest incidence of the disease of all states. Within the state, New York City has by far the most infections, but the rise of new cases in the city has begun to slow, according to recent data.

The vast majority of counties that had confirmed COVID-19 cases seven days ago have far more cases today. In every state there is one county where new confirmed cases have grown the fastest in the past week.

Click here to see the counties in every state where COVID-19 is growing the fastest right now.
Click here to see our methodology.

The speed at which the coronavirus spreads in communities across the United States is likely to be closely related to how well residents practice social distancing. In an interview with 24/7 Wall St., Mark Siedner, associate professor of infectious diseases at Harvard University and clinician at Massachusetts General Hospital, explained that with no vaccine and no effective treatment options, “social distancing is the only intervention we have currently to stop the epidemic.”

Studies have shown statewide social distancing measures to be associated with a decrease in U.S. COVID-19 growth. Many of the hotspots that have more recently emerged, and a significant number of states where cases are growing the fastest, are places that have not implemented social distancing policies. Other recent studies have shown declines in population mobility to be correlated with a slower spread of COVID-19 on the county level. These are the states where the virus is spreading the fastest right now.

According to Siedner, social distancing measures and testing depend heavily on one another. “Social distancing relies on testing to be effective because if you don’t know the rate at which the epidemic is growing or hopefully slowing, [then] you don’t know when to relax it [and] you don’t know when to institute it.”

Testing data for counties is not published widely enough to include in this list, but it is likely that counties reporting more COVID-19 cases are also testing more of their populations. Testing statistics published by state health departments show that the states that are testing larger shares of their populations are reporting higher confirmed cases per capita.