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U.S. and Arizona flags.

For the first time since the 1960 census, Arizona will not pick up an additional U.S. congressional seat. This is despite expectations from experts that the state would add a 10th seat. 

Arizona's nearly 12% growth rate since 2010 reached almost twice the national average but placed the state only ninth highest in the nation. It was eighth highest in terms of population added — 759,485.

Arizona had the eighth worst rate of self-response in the country, which some critics cite as a contributing factor. The state had added a congressional seat every census since 1960. Gov. Doug Ducey had no immediate response, but a prepared statement from AZ Census 2020 said it was disappointing that Arizona didn’t receive an additional seat.

Kimball Brace, president of Election Data Services, says when he looks at other states like Florida and Texas, which also fell short of expectations, he sees a common thread: large Hispanic populations. 

“I think the Trump administration and the stuff that they did with doing the citizenship question I think hurt all of those states. And it's caused people to not respond to the census. And as a result, they're all lower than what they were anticipating," Brace said. 

Altogether, the U.S. population rose to 331,449,281 last year, the Census Bureau said, a 7.4% increase that was the second-slowest ever. Experts say that paltry pace reflects the combination of an aging population, slowing immigration and the scars of the Great Recession, which led many young adults to delay marriage and starting families.

The new allocation of congressional seats came in the U.S. Census Bureau's first release of data from a 2020 headcount. The numbers generally chart familiar American migration patterns but also confirm one historic marker: For the first time in 170 years of statehood, California is losing a congressional seat, a result of slowed migration to the nation’s most populous state, which was once a symbol of the country’s expansive frontier.

The census release marks the official beginning of the once-a-decade redistricting battles. The numbers released Monday, along with more detailed data expected later this year, will be used by state legislatures or independent commissions to redraw political maps to account for shifts in population.

Those shifts have largely been westward. Colorado, Montana and Oregon all added residents and gained seats. Texas was the biggest winner — the second-most populous state added two congressional seats, while Florida and North Carolina gained one. States losing seats included Illinois, Michigan, Pennsylvania and West Virginia.

The overall numbers do confirm what demographers have long warned — that the country's growth is stalling out. Many had expected growth to come in even below the 1930s levels given the long hangover of the Great Recession and the drying up of immigration, which came to a virtual halt during last year's pandemic.

EDITOR'S NOTE: The story has been updated to correct Arizona's growth rate and added population.