One year later, cases of Covid-19 have reached all American counties

A year ago, health officials announced the first confirmed case of Covid-19 in the United States in Snohomish County, Washington state, near Seattle. Less than 11 months later, the virus reached an isolated Hawaiian enclave established over a century ago for patients with leprosy, now known as Hansen’s disease.

It appears to be the last county in the United States to record a case of coronavirus, according to a Wall Street Journal review of state registers and data collected by Johns Hopkins University.

Since the first reported case, Covid-19 has run across the United States, infecting at least 24 million Americans and killing more than 400,000. The virus spread from large cities to sparsely populated rural counties before reaching ultimately even the most remote areas that have worked diligently to keep the virus at bay.

To identify the last of the more than 3,000 counties that appear to be affected by the virus, the Journal looked at data from Johns Hopkins and individual states to verify that Covid-19 has reached every county of the 48 contiguous states and Hawaii. Alaska does not have formal counties, but its coronavirus data dashboard shows cases in all boroughs and census areas in the state that the state is reporting for.

During the year, the list of hardest hit counties has generally gone from populated to small counties before the current winter push.