© Elijah Nouvelage/Bloomberg News

WASHINGTON—Government officials across the U.S. are using location data from millions of cellphones in a bid to better understand the movements of Americans during the coronavirus pandemic and how they may be affecting the spread of the disease.

The federal government, through the Centers for Disease Control and Prevention, and state and local governments have started to receive analyses about the presence and movement of people in certain areas of geographic interest drawn from cellphone data, people familiar with the matter said. The data comes from the mobile advertising industry rather than cellphone carriers.

The aim is to create a portal for federal, state and local officials that contains geolocation data in what could be as many as 500 cities across the U.S., one of the people said, to help plan the epidemic response.

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The data—which is stripped of identifying information like the name of a phone’s owner—could help officials learn how coronavirus is spreading around the country and help blunt its advance. It shows which retail establishments, parks and other public spaces are still drawing crowds that could risk accelerating the transmission of the virus, according to people familiar with the matter. In one such case, researchers found that New Yorkers were congregating in large numbers in Brooklyn’s Prospect Park and handed that information over to local authorities, one person said. Warning notices have been posted at parks in New York City, but they haven’t been closed.

The data can also reveal general levels of compliance with stay-at-home or shelter-in-place orders, according to experts inside and outside government, and help measure the pandemic’s economic impact by revealing the drop-off in retail customers at stores, decreases in automobile miles driven and other economic metrics.

The CDC has started to get data through one project, dubbed the Covid-19 Mobility Data Network, that is being coordinated through an ad hoc coalition of epidemiologists at Harvard, Princeton, Johns Hopkins and other universities along with numerous tech companies and data providers—all working in conjunction with the White House and others in government, the people said.

The CDC and the White House didn’t respond to requests for comment.

The growing reliance on mobile phone location data continues to raise concerns about privacy protections, especially when programs are run by or commissioned by governments.



Wolfie Christl, a privacy activist and researcher, said the location-data industry was “covidwashing” what are generally privacy-invading products.

“In the light of the emerging disaster, it may be appropriate to make use of aggregate analytics based on consumer data in some cases, even if data is being gathered secretly or illegally by companies,” said Mr. Christi. “As true anonymization of location data is nearly impossible, strong legal safeguards are mandatory.” The safeguards should limit how the data can be used and ensure it isn’t used later for other purposes, he said.

Privacy advocates are concerned that even anonymized data could be used in combination with other publicly accessible information to identify and track individuals.

Some companies in the U.S. location-data industry have made their data or analysis available for the public to see or made their raw data available for researchers or governments. San Francisco-based LotaData launched a public portal analyzing movement patterns within Italy that could help authorities plan for outbreaks and plans additional portals for Spain, California and New York. The company Unacast launched a public “social distancing scoreboard” that uses location data to evaluate localities on how well their population is doing at following stay-at-home orders.

Other state and local governments too have begun to commission their own studies and analyses from private companies. Foursquare Labs Inc., one of the largest location-data players, said it is in discussions with numerous state and local governments about use of its data.

Researchers and governments around the world have used a patchwork of authorities and tactics to collect mobile phone data—sometimes looking for voluntary compliance from either companies or individuals, and in other cases using laws meant for terrorism or other emergencies to collect vast amounts of data on citizens to combat the coronavirus threat.

Massachusetts Institute of Technology researchers have launched a project to track volunteer Covid-19 patients through a mobile phone app. Telecom carriers in Germany, Austria, Spain, Belgium, the U.K. and other countries have given data over to authorities to help combat the pandemic. Israel’s intelligence agencies were tapped to use antiterrorism phone-tracking technology to map infections.

In the U.S., so far, the data being used has largely been drawn from the advertising industry. The mobile marketing industry has billions of geographic data points on hundreds of millions of U.S. cell mobile devices—mostly drawn from applications that users have installed on their phones and allowed to track their location. Huge troves of this advertising data are available for sale.

The industry is largely unregulated under existing privacy laws because consumers have opted-in to tracking and because the data doesn’t contain names or addresses—each consumer is represented by an alphanumeric string.

Cellphone carriers also have access to massive amounts of geolocation data, which is granted much stricter privacy protection under U.S. law than in most other countries. The largest U.S. carriers, including AT&T Inc. and Verizon Communications Inc., say they have not been approached by the government to provide location data, according to spokespeople. There have been discussions about trying to obtain U.S. telecom data for this purpose, however the legality of such a move isn’t clear.

Write to Byron Tau at byron.tau@wsj.com