COVID migration patterns fuel changes in LI's population

Nassau County's population declined slightly in July 2021 from its 2020 census count, while Suffolk County's rose a bit — and the state's total dropped too, impacted by losses in New York City, according to new estimates the U.S. Census Bureau released Thursday.

Census officials cited the pandemic as a factor, noting new regional trends in migration and an increase in deaths related to COVID-19.

"The pattern of the domestic migration is very different" because of the virus, said Jan Vink, a researcher with Cornell University's Program on Applied Demographics, which conducted an analysis of the Census Bureau's 2021 Vintage Population Estimates. "Within Long island, for example, Suffolk had more people moving in than moving out."

The increase in Suffolk was very small: 424 people, or 0.028%, during the period, to 1,526,344. But it goes against recent trends for the county.

"Every year in the last decade [Suffolk] lost a lot of population, almost 10,000 every year, because more people were moving out," while Nassau had seen gains, Vink noted.

But Nassau's population dropped 4,867 between its 2020 census count and July 1, 2021, estimates: from about 1.396 million people to about 1.391 million, or 0.35%.

Most counties in the state registered losses, putting New York's total population at about 19.8 million, down 1.8% — about 365,000 people — from the census count of about 20.2 million, according to the Cornell program's analysis.

"Eight out of 10 regions lost population between April 1, 2020, and July 1, 2021," the university's report states. It added, "Of 62 counties in New York, 46 lost population since the last census." 

New York City saw the largest declines in the state.

According to census estimates, Manhattan, or New York County, registered the largest percentage drop in population among counties nationwide, 6.9%, and the second-largest numeric drop in population between July 2020 and July 2021, after Los Angeles County, California. 

Four of New York City's five boroughs were in the top 10 of the nation's counties with the highest percentage population declines. In addition to Manhattan, Brooklyn, or Kings County, had a 3.5% decline, ranking sixth; the Bronx had a 3.2% decline, ranking eighth; and Queens had a 3.1% decline, ranking ninth.

Vink cited the pandemic, prompting many people to leave New York City for places like the Hamptons in Suffolk, and elsewhere.

"A lot of those people ended up on Long Island, also upstate New York and in surrounding states," Vink said. 

A significant factor in population declines for some counties, census officials said, was an increase in deaths.

"More than 73% (2,297) of U.S. counties experienced natural decrease in 2021, up from 45.5% in 2019 and 55.5% in 2020," the bureau said in a news release. "Natural decrease occurs when there are more deaths than births in a population over a given time period. In 2021, fewer births, an aging population and increased mortality — intensified by the COVID-19 pandemic —contributed to the rise in natural decrease." 

But while many counties experienced a "natural decrease," many also saw population increases through domestic migration, or people moving into their counties.

The bureau said just over 65% of the nation's more than 3,000 counties experienced an increase in domestic migration. But it singled out two counties that experienced the greatest net migration loss: Los Angeles County, where 179,757 people moved away, and Manhattan, where 113,642 left between 2020 and 2021. 

The 2021 population estimates cover 3,143 counties, 384 metropolitan statistical areas and 543 micropolitan, or small city, statistical areas.

The bureau calculates the estimates by integrating data from the most recent decennial census, in this case the 2020 census, along with current data on births, deaths and migration.

By Olivia Winslow

olivia.winslow@newsday.com@newsollie