With many state and local governments starting to relax stay-at-home orders, it’s instructive to examine just how concentrated the spread of COVID-19 has been in the U.S.

Although all U.S. states have reported cases of COVID-19, the distribution of the cases and deaths has remained heavily concentrated in a small number of states, and among a small number of counties within all states.

For instance, as of May 4, just 10 states account for 70% of all U.S. cases and 77% of all deaths. Together, New York and New Jersey alone account for 38% of all cases and 48% of total COVID-19 deaths.

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Just five states—New York, New Jersey, Massachusetts, Illinois, and California—account for 54% of all of the confirmed cases in the U.S. and 61% of all coronavirus deaths.

These state-level figures do not, however, adequately describe the concentrated nature of the spread of COVID-19.

As the first chart shows, the 30 counties with the most COVID-19 cases account for 50% of all the cases in the U.S. (and 57% of all deaths). That is, just 1% of the counties in the U.S. are responsible for half of the country’s coronavirus cases and more than half of the deaths.

Of those 30 counties, 24 are in the Northeast corridor between Philadelphia and Boston, the passageway served by a commuter railway system that runs through Manhattan. Overall, just 11% of the counties in the U.S. contain nearly 95% of all the COVID-19 deaths.

Just as important, as the second chart shows, 52% of all U.S. counties have had zero COVID-19 deaths as of May 4.

Also as of May 4, 13 states have deaths that remain unallocated to respective counties. At most, those allocations could reduce the number of zero-death counties by 2 percentage points.

The chart also illustrates that 66% of all U.S. counties have no more than one coronavirus death, 80% have five or fewer, 86% have 10 or fewer, and 89% have fewer than 15.

Put another way, only about 10% of the counties in the U.S. have 15 or more COVID-19 deaths, and throughout the epidemic, the spread of COVID has remained highly concentrated in a handful of geographic locations in the U.S.