The downtown Denver skyline, as seen from Civic Center Park on Oct. 3, 2020. 

The pandemic intensified population trends, with Americans leaving many of the nation’s most densely populated and costly cities, according to data released Thursday by the U.S. Census Bureau.

The same one year period showed a stark increase in deaths outpacing births across the country.

In Denver, the population dipped by nearly 1% in the first year of the global coronavirus pandemic. The dip of more than 6,000 residents between July 2020 and July 2021 is the first population decline the city and county has seen since the mid-2000s.

In Denver, and most other counties in Colorado, births outnumbered deaths, meaning the decline in population was driven by out-migration.

Denver’s loss was balanced by growth in the surrounding counties, leaving the broader metro-area with a small population increase, during the pandemic, after years of consistently booming growth, according to the new census numbers. Jefferson County, and to a lesser extent Arapahoe County, also lost population, but not as much as Denver. Douglas County grew the most with almost 9,000 new residents, and Adams County grew by almost 2,000.

The Colorado Springs area continued to grow during the first year of the pandemic, with El Paso County adding about 6,000 residents, growth of about 0.8%, the data showed.

Colorado’s statewide population did continue to grow during pandemic but at a slower pace. The state added almost 28,000 new residents — growth of about one-half of a percent, significantly below the fast growth Colorado has seen for at least the past decade.

The exodus from the biggest U.S. metropolitan areas was led by New York, which lost almost 328,000 residents. It was driven by people leaving for elsewhere, even though the metro area gained new residents from abroad and births outpaced deaths.

Metropolitan Los Angeles lost almost 176,000 residents, the San Francisco area saw a loss of more than 116,000 residents and greater Chicago lost more than 91,000 people from 2020 to 2021. The San Jose, Boston, Miami and Washington areas also lost tens of thousands of residents primarily from people moving away.

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On the flip side, the Dallas area grew by more than 97,000 residents, Phoenix jumped by more 78,000 people and greater Houston added 69,000 residents. In the Phoenix metropolitan area, growth was driven by moves from elsewhere in the U.S., while it was propelled by a combination of migration and births outpacing deaths in Dallas and Houston.

The U.S. Census Bureau’s Vintage 2021 estimates also showed micro areas — defined as having a core city of less than 50,000 residents — gaining population from mid-2020 to mid-2021, after years of slow growth or declining population. The small population gains were driven by people moving there, as deaths continued to outpace births in many of these communities. Growth in micro areas was led by Kalispell, Mont.; Jefferson, Ga.; and Bozeman, Mont.

Demographer William Frey said he believes the growth of micro areas and decreases in the biggest metros will be temporary, taking place at the height of people moving during the pandemic when work-from-home arrangements freed up workers from having to go to their offices.

“There is clearly a dispersion, but I think it’s a blip,” said Frey, senior fellow at the Brookings Institution’s metropolitan policy program, Brookings Metro. “We’re at one of the lowest levels of immigration in a long, long time, and that affects big metros like New York, Los Angeles and Chicago. That is going to come back. With the natural decrease, we will go back to normal.”

Meanwhile, almost three-quarters of U.S. counties experienced a natural decrease from deaths exceeding births, up from 55.5% in 2020 and 45.5% in 2019. The trend was fueled by the COVID-19 pandemic, as well as fewer births and an aging population.

“You have more older Americans, and birth rates are low so you don’t have many children being born, and then along comes COVID, and it hits older adults the most, often in rural areas without access to good health care,” said Kenneth Johnson, a senior demographer at the University of New Hampshire. “It’s like a perfect storm, if you will, that produced this natural decrease.”

Pittsburgh and Tampa had the largest natural decreases of U.S. metropolitan areas, in the range of 10,000 residents each.

Denver Gazette reporter Evan Wyloge and The Associated Press contributed to this report.