The United States recently hit a grim milestone with 100,000 known deaths attributable to the novel coronavirus. The U.S. has been the hardest hit country in the world with more than 1.7 million confirmed cases — or nearly 30% of the global total to date.

Just as cases of the virus have not been evenly spread across the globe, infections are highly concentrated in certain pockets of the country — primarily in the densely-populated Northeastern and mid-Atlantic region (here is a look at the states where the virus is spreading fastest right now.)

Still, in nearly every state — even in those where the number of known cases per capita has remained low — there are hotspots where the number of diagnosed cases per capita is approaching or well exceeding the national figure. As of May 27, there have been 519 cases of the virus for every 100,000 people nationwide.

Using COVID-19 data from state and local health departments, and population data from the U.S. Census Bureau, 24/7 Wall St. reviewed COVID-19 cases in over 3,000 U.S. county and county equivalents to determine the county in each state with the most cumulative confirmed cases, adjusted to the population. In the counties on this list, the prevalence of the disease ranges from 71 cases to more than 14,000 cases per 100,000 people. Data in every state is current as of May 27, with the exception of Connecticut, where data is as of May 26, the most recent available.

The most effective virus containment tool we have had at our disposal is social distancing. It is therefore no coincidence that many of the counties on this list are home to places where social distancing is difficult, if not impossible. These places include prisons — such as those in Colorado’s Logan County and Tennessee’s Trousdale County — and industrial plants, such as the JBS meat plants in Nobles County, Minnesota and Moore County, Texas.

It is important to note that infection rates at national, state, and county levels only reflect known cases. For a variety of reasons, in much of the country, there are likely thousands of COVID-19 infections that are going undetected. This is how COVID-19 is being underreported in most states.

Click here to see the counties in every state with the highest number of COVID-19 cases.