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A skyline view of Phoenix.

Officials in some of the largest U.S. cities — including Phoenix — have challenged their 2020 population counts because they disagree with U.S. Census Bureau tabulations.

Phoenix awaits a response to a challenge of its “group quarters count,” a reference to people in dorms, nursing homes, jails and treatment facilities.

According to a letter from Mayor Kate Gallego, obtained through a public records request by the Associated Press, she claims 3,500 people in nearly 200 facilities were missed.

Gallego argued two jails were overlooked, along with addiction treatment centers, a group home for people with diabetes and Alzheimer's disease as well as a live-in facility for juveniles needing mental health treatment. 

According to published census data, Phoenix increased its population by about 11 % from 2010 to 2020, earning it the distinction of “the fastest-growing big city in the U.S. between” that time period.

At 1.6 million residents, it’s the fifth most populous U.S. city according the data.