As Heritage Foundation researchers have demonstrated throughout the pandemic, the spread of COVID-19 in the U.S. has been extremely concentrated in a small number of states—and among a small number of counties within all states.

As of May 11, for example, 10 states accounted for almost 70% of all U.S. cases and nearly 75% of all deaths (but only 52% of the population). Together, New York and New Jersey alone account for 35% of all cases and 44% of total COVID-19 deaths, though only 9% of the U.S. population.

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

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The 30 counties with the most COVID-19 cases, for example, account for 48% of all the cases in the U.S. and 55% of all deaths, three to four times greater than their 15% share of the U.S. population. 

That is, just 1% of all counties, representing 15% of the U.S. population, are responsible for almost half of the country’s COVID-19 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, only about 10% of all counties contain 95% of all the COVID-19 deaths, even though they account for 64% of the population.

Just as important, 50% of all counties (with 10% of the U.S. population) have zero COVID-19 deaths as of May 11. In fact, 63% of all counties (with 15% of the population) have no more than one COVID-19 death each. 

So, while 1% of counties (mostly in the Northeast) have more than half of all COVID-19 deaths in the U.S., 63% of counties have no more than one COVID-19 death each—and both groups represent the same share of the U.S. population.

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.

The Heritage Foundation’s interactive COVID-19 tracker helps put these levels of concentrated cases in perspective. It provides county-level data that includes total cases, total cases as a percentage of the population, where that percentage ranks among all 3,145 counties, and a population density measure.

The tracker also describes whether the trend of cases is increasing or decreasing over the prior 14 days, and provides a visual depiction of new cases during this time period.

The information shows just how difficult it can be to use only one metric to gauge whether a county is doing well. 

For instance, Jersey County, Illinois, on the state’s border with Missouri, has had an increasing case trend during the past 14 days. As the chart shows, however, the county has not had more than one new case per day since April 26.

Furthermore, the fact that Jersey County ranks almost squarely in the middle of all U.S. counties with a case total of just 0.08% of its population affirms that most counties have a relatively small number of COVID-19 cases.

Readers are invited to explore the information in the tracker and check back frequently for updates.