By Connor O’Brien

Key findings

  • Large urban counties have suffered severe declines in their population of young children. While overall population growth in such counties resumed in 2023 (mainly due to immigration) for the first time since the pandemic, the population of young kids continued to decline. 
  • The country’s very largest cities have experienced shocking declines in their population of young children. The under-five population has fallen by 18 percent in New York City, 15 percent in Cook County, Illinois (Chicago), and 14 percent in Los Angeles County since 2020. 
  • Birth rates in large urban counties have declined twice as fast as in rural counties over the last decade. 
  • More than 800,000 people moved out of large urban counties last year, twice the pre-pandemic rate. 
  • The number of young children in most counties across the country is on the decline. The number of children under five fell in 58 percent of all counties last year and has fallen in two-thirds of all counties since 2020.

Introduction: The under-five population is shrinking across the country. 

The U.S. population is rapidly growing older as birthrates fall. Consequently, the population of children is declining, particularly that of young children under five. Between 2022 and 2023, the under-five population fell by 146,000, or 0.8 percent. The nation now has 890,000 fewer young children than before the pandemic—a 4.6 percent decline. 

Most counties across the country are home to a declining number of young kids, with profound consequences for school systems and long-term population growth prospects. In 2023, 58 percent of all counties in the U.S. experienced declines in their under-five populations. Since April 2020, two-thirds of all counties’ under-five populations have shrunk.

The pandemic is long over, but the exodus of young families from big cities continues.

The pandemic era sparked a dramatic outflow of families with young kids from large urban counties to suburban, exurban, and rural communities. Between July 2020 and July 2021, the under-five population in large urban counties fell 3.9 percent, much faster than such counties’ overall population decline of 0.7 percent. As the pandemic receded and urban cores began to recover from its shock, overall population losses in major cities ebbed and have begun to reverse.

However, steep declines in the under-five population in large urban counties have continued long after the pandemic’s end. Last year, the population of young children in these counties continued to fall much faster than in the rest of the country; the so-called “urban family exodus” has continued. 

Taking stock: Major cities have seen shocking declines in their population of young kids. 

Since April 2020, large urban counties’ under-five population has fallen by more than eight percent, nearly twice as large as the decline of kids under five nationwide. Notably, only exurban counties have added young kids.

Some of the country’s highest-profile large cities have seen the biggest declines. In New York City, the population of kids under five as of July 2023 was a full 18.3 percent lower than it was in April 2020. That is a decline of 100,000 young children living in New York City in just 39 months.

But New York is not alone. Since April 2020, San Francisco’s under-five population has fallen by 15.4 percent, Los Angeles County’s by 14.2 percent, and Cook County Illinois’ (Chicago and its suburbs) by 14.6 percent. Other parts of California including Santa Clara (-13.9 percent), San Mateo (-13 percent), and Orange (-13 percent) counties are also among the biggest losers. 

Birth rates are declining the fastest in large urban counties. 

The decline in young children in American cities over the past few years is largely driven by the out-migration of young families and declining birth rates across the entire country. However, birth rates appear to be falling fastest in the country’s most urbanized counties and slowest in rural areas. 

Since 2010-11, the number of births per 100 women age 15 to 44 has declined the fastest in large urban counties, from 6.4 to 5.4. Declines in mid-sized and small urban counties have been slightly less. In rural counties, the decline in birth rates over this span has been half that of large urban counties.

Out-migration from big cities remains twice its pre-pandemic rate. 

While the overall population of large urban counties has started to grow modestly again, it is not because Americans have flooded back. Rather, immigration from abroad and the contribution from “natural change”—driven entirely by declining deaths, not rising births—have canceled out high out-migration. 

Nearly 800,000 people left large urban counties last year, on par with 2022. While below early-pandemic out-migration, this rate remains double pre-pandemic trends. Since 2020, 2.7 million residents of large urban counties have moved away, twice as many as in the three years leading up to the pandemic.

Sprawling Sun Belt counties are among the few bright spots adding young families. 

While the number of young kids is shrinking in most places, some larger counties across the Sun Belt and not within major urban cores are seeing growth. 

Polk County, Florida, home to Lakeland and positioned right between Orlando and Tampa, has added 5,100 young kids on net since April 2020, a 12.5 percent increase. That is the largest increase of any county in the country. 

Collin County, Texas, just outside of Dallas, has added more than 4,900 kids (+7.8 percent), while Montgomery County, Texas outside Houston has added over 4,400 (+11.1 percent). 

A similar pattern replicates across many parts of the Southeast. While the region’s largest cities like Atlanta, Houston, and Miami are home to a shrinking population of young families, counties on the edges of their metro areas are often rare bright spots of growth. 

Many of these counties are considered exurban under our typology. This group of about 80 counties has seen explosive population growth since the pandemic, particularly in the Southeast. Overall population growth in exurban counties has been 5.5 percent since April 2020, much faster than any other county type and the country overall. In some of the largest exurban counties like Pinal County, Arizona, Osceola County, Florida, and Lake County, Florida, cumulative growth over just the last three years has exceeded 10 percent. Much of this growth has come from the in-migration of families with young children. 


The pandemic era dealt a body blow to the economic and demographic health of many of America’s major cities. It sent young families in particular fleeing to smaller cities, suburbs, or even rural parts of the country. But the pandemic is decidedly over, and young families are still not returning. Meanwhile, birth rates are declining faster in large urban counties than anywhere else in the country. Combined, these trends mean that the population of young families living in the country’s major cities is rapidly shrinking. 

Appendix: Definitions

Large urban counties contain the population-weighted center of a large city (a population of 250,000 or higher). Additionally, any county where 100 percent of the population lives in a large city is given this definition as well. Mid-sized urban counties contain the population-weighted center of a mid-sized city (a population of 100,000-250,000) and are in a metropolitan area without a large city. Small urban counties contain the population-weighted center of a small-sized city (a population of 50,000-100,000) and are in a metropolitan area without a large or mid-sized city. Suburban counties are also understood to be near an urban area, unlike exurban counties that are on the periphery of an urban area. To qualify as suburban, a county must have at least half of its population living in a large or mid-sized suburb or urban area based on NCES definitions. All counties previously defined as large, mid-sized, or small urban counties are then excluded, with the remainder defined as suburban. Exurban counties are metropolitan counties that are more rural and less suburban but are still in the orbit of a large or mid-sized city. Consequently, counties can only be defined as exurban if they are in a metropolitan area that also contains a large or mid-sized city. Additionally, for a county to qualify as exurban, less than 50 percent of its population can live in a large or mid-sized suburban or urban area based on NCES definitions, and at least 25 percent of the county is non-rural. All counties previously defined as large, mid-sized, or small urban counties are excluded. Metro rural counties are metropolitan counties not classified under the above categories. Nonmetro rural counties are all non-metropolitan counties.

Demographic Trends  

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