African American and white residents continue to leave Cook County as the Asian and Hispanic population grows modestly, new data from the U.S. Census shows.

Cook County still has the largest African American population of any U.S. county — 1.2 million. But that number is dropping; the Census Bureau estimates the county lost over 12,000 African Americans between 2017 and 2018.

Population loss can have a significant impact, as local governments struggle to fund operations.

“When you lose population you lose taxpayers,” said Chicago-based demographer and public policy consultant Rob Paral.

“Government has to provide many of the same services regardless of the number of people who live here, like road improvements. So if fewer people live in an area, that means a greater cost burden per person on those who remain.”

That population loss is starker when compared to 2010 census figures.

From 2010 to 2018, the county’s African American population fell by 5.8% from 1,311,698 million to 1,236,170 — a loss of over 75,000 people.

Cook County’s white population also fell for the fourth year in a row, with the loss of about 21,000 people — a drop of 0.6%.

In the city, however, the white population is growing. From 2010 to 2017, the most recent data available, Chicago’s white population grew 17%, from 1,189,113 to 1,394,263.

Overall, Chicago’s population was 2.7 million in 2018, down about 7,000 from the year before.

“You have an aging and declining white population in the suburbs, but in the city you have this booming population,” Paral said.

However, Cook County as a whole is aging regardless of racial or ethnic breakdown. From 2010 to 2017, Cook County loss nearly 161,000 residents that were 29 years old or younger. At the same time, it gained over 157,000 residents ranging from 50 years old to 79 years old — an 11.5% increase.

Cook County is seeing some growth among other demographics.

The Asian population, for one, has steadily increased. In 2018, the county’s Asian population reached 408,151. That was up more than 75,000 compared to 2010.

Hispanics also increased, with 78,000 more county residents since the 2010 census — a gain of more than 6%. That growth has slowed, however, to a modest 0.3% from 2017 to 2018.

Cook County — still the second-most-populated in the country, with nearly 5.2 million residents — suffered the largest overall population loss nationwide.

Between July 2017 and July 2018, the bureau estimates, more than 24,000 residents left, a 0.5% drop. That’s loss among the five largest counties. Los Angeles County — with over 10 million residents — saw a 0.1% drop. Harris County (Houston) increased by 0.7%; Maricopa County (Phoenix) jumped 1.9%; and San Diego County grew 0.5%.

It gets worse in the context of 2010 figures.

From 2010 to 2018, Cook County’s population fell by 0.3%; all four of those other areas increased: Los Angeles County (2.9%), Harris County (14.8%), Maricopa County (15.6%) and San Diego County (8%).

Paral said the issue of Cook County’s population loss is reflected in many counties in the Midwest. People are simply moving to farther south and west, he said.

Manny Ramos is a corps member in Report for America, a not-for-profit journalism program that aims to bolster Sun-Times coverage of Chicago’s South and West sides.