Other aspects of the count, though, are facing unexpected obstacles. Already, a multi-day nationwide count of roughly a half-million homeless people has been put off. Processing of mailed-in census forms has slowed because the bureau shaved its staff at regional centers in Jeffersonville, Ind., and Tuscon, Ariz. And social-distancing cuts in the bureau’s call center work force have slowed down responses to people who want to complete the census by phone or need other kinds of help.

What plans have been disrupted or canceled?

The bureau wants as many households as possible to respond to the census early because tracking down non-responders and persuading them to answer the questionnaire is hugely expensive and difficult. So a massive publicity and public awareness blitz was scheduled to reach out on federal, state and local levels.

But the coronavirus has upended huge parts of that campaign, which envisioned crowded public events centered on the census. Promise Neighborhoods, an Allentown, Pa., group, had to scrap a local basketball tournament that would have drawn hundreds. Chicago is setting up 100 computer kiosks for online census work at gathering points, but pandemic-spooked residents are not gathering to use them. Detroit census organizers canceled 90 public events that were supposed to promote the head count.

Unable to draw crowds or even to knock on doors, census supporters are improvising new ways to drum up response. Detroit plans to enlist 600 neighborhood block groups that will compete to achieve the highest census response. One California group has abandoned its door-to-door campaign and is instead handing out census information at places like food banks. State and local campaigns everywhere have ramped up social media advertising. In Pennsylvania’s Lehigh Valley, a campaign is targeting Hispanic households that are traditionally hard to count by inserting Spanish-language ads in Facebook videos that are reached via Spanish internet addresses.