Denver’s long-running population boom revved up last year — but the surge again was eclipsed in new census estimates by growth in El Paso County, threatening its status as the state’s largest county.

The dual city and county of Denver absorbed 11,053 more residents in the year that ended July 1, the date used by the U.S. Census Bureau each year as the peg for official annual population estimates. That nearly 1.6 percent growth rate put Denver’s population at 716,492.

After two years of slowing growth, Denver picked up the pace between mid-2017 and mid-2018, according to Denver Post analysis of census figures set for release Thursday. A year earlier, the population growth rate was 1.3 percent, according to revised census estimates for 2016-2017.

But the city’s average net increase of 921 people per month during that period pales in comparison with the 1,566-a-month growth rate in 2014-15, the high-water mark of the last decade.

The new estimates bring Denver’s remarkable run into clearer focus, showing that the city has grown by just under 20 percent since 2010. The urban boom has come with a housing affordability crunch, increased traffic and angst over development, all issues that are front and center in the May 7 election for mayor and City Council.

Colorado’s population neared 5.7 million in the new census figures, up 1.4 percent. One notable national ranking was the Greeley metro area’s status as the seventh-fastest-growing metropolitan area (falling from third place in 2017) — in part the result of the area’s booming oil and gas industry.

Renewed battle for largest county

El Paso County — home to Colorado Springs — continued to outpace Denver’s growth, in both numerical and percentage terms, for the third year running. Its estimated population of 713,856 on July 1 reflects a net increase of 13,056 people, or nearly 1.9 percent.

Denver’s feverish growth earlier in the decade helped it overtake El Paso for state’s largest county in 2016, but now the roles have reversed. If the trends continue, El Paso could be back on top within two years.

Colorado’s fastest-growing counties

After Denver and El Paso counties, Weld County (home to Greeley) notched the third-largest numerical population increase (9,031) among Colorado’s 64 counties during the one-year period. It was followed by Adams (7,440) and Douglas (7,108). In the Denver metro area, Douglas, which grew by 2.1 percent, was the only county to outpace Denver in percentage terms.

The counties with the top growth rates were all small — San Juan (7.2 percent), Huerfano (3.7 percent) and Park (3.5 percent). Several rural counties showed slight losses of population, led by Sedgwick, Rio Blanco and Logan.

Denver: Newcomers vs. births

The tremendous growth absorbed by Denver since 2010 is mostly — but not all — from newcomers. The census breakdowns include an estimate that 70,924 people moved to Denver from elsewhere in the United States or the world, accounting for about 63 percent of its growth during the decade.

Most of the rest — nearly 36 percent, or 40,277 people — was attributed to natural population growth (births minus deaths), with a tiny portion uncategorized.

Metro area’s population growth

The census estimates put the population as of July 1 for the Denver-Aurora-Lakewood metropolitan statistical area, the nation’s 19th largest, at 2.9 million, up 1.4 percent in the previous year. But that definition includes some rural areas and leaves out Boulder County.

Using the more common definition of the seven-county metro area — Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas and Jefferson — the Denver region’s population was nearly 3.2 million. That reflects an increase of 1.3 percent in the prior year and nearly 15 percent since 2010.