WASHINGTON — Census Block 1002 in downtown Chicago is wedged between Michigan and Wabash Avenues, a glitzy Trump-branded hotel and a promenade of cafes and bars. According to the 2020 census, 14 people live there — 13 adults and one child.

Also according to the 2020 census, they live underwater. Because the block consists entirely of a 700-foot bend in the Chicago River.

If that sounds impossible, well, it is. The Census Bureau itself says the numbers for Block 1002 and tens of thousands of others are unreliable and should be ignored. And it should know: The bureau’s own computers moved those people there so they could not be traced to their real residences, all part of a sweeping new effort to preserve their privacy.

That paradox is the crux of a debate rocking the Census Bureau. On the one hand, federal law mandates that census records remain private for 72 years. That guarantee has been crucial to persuading many people, including noncitizens and those from racial and ethnic minority groups, to voluntarily turn over personal information.

On the other, thousands of entities — local governments, businesses, advocacy groups and more — have relied on the bureau’s goal of counting “every person, only once and in the right place” to inform countless demographic decisions, from drawing political maps to planning disaster response to placing bus stops.

The 2020 census sunders that assumption. Now the bureau is saying that its legal mandate to shield census respondents’ identities means that some data from the smallest geographic areas it measures — census blocks, not to be confused with city blocks — must be looked at askance, or even disregarded.

And consumers of that data are unhappy.