Loudoun County has joined Fairfax and Prince William counties as one of the three most populous in Virginia, according to an annual state population estimate released last week by University of Virginia researchers.

Although population growth slowed across much of the state last year, Loudoun had a steady influx of new residents, pushing the county — one of the fastest-growing in the nation — ahead of Chesterfield County to claim third place in the state. Fairfax and Prince William also showed steady growth, according to the report.

Monday’s report, issued by the Weldon Cooper Center for Public Service, showed that Virginia’s population overall grew between 2012 and 2013 by less than 1 percent, or about 74,500 people. But between the April 2010 census and the July 1, 2013, estimate in the report, Loudoun had a population increase of more than 11 percent and a total of nearly 348,000 residents.

Fairfax, topping the list with an estimated 1.1 million residents, had a population increase of 3.3 percent in the same period. Prince William, in second place with a population of about 431,000, grew by more than 7 percent, researchers said.

“Loudoun, Fairfax, Prince William, and Arlington counties and the city of Alexandria continue to experience considerable growth,” Hamilton Lombard, the researcher who prepared the estimates, said in a statement. “Together, they accounted for more than half of the growth in the commonwealth since 2010, compared to 44 percent between 2000 and 2010.”

Loudoun has been consistently ranked among the fastest-
growing counties in the region and in the nation, with a burgeoning minority population fueling much of its growth. According to 2010 census data, most of the county’s growth and demographic shifts are concentrated in its eastern suburbs, home to much of the county’s commercial and residential development. Loudoun’s Dulles Technology Corridor has also been a major draw in the past two decades.

Fredericksburg was the fastest-growing locality since 2010, increasing by more than 15 percent, the report said. Urban localities in the state experienced above-
average growth, marking a change from the previous decade. Between 2000 and 2010, suburban areas grew much faster than urban communities in Virginia, a trend that has reversed, researchers said.

Virginia’s overall population rose to nearly 8.3 million, the report said. Although last year’s growth was the slowest in the state since before the recession, Virginia posted the 14th-highest growth rate and the seventh-
largest population gain in the nation, the report said.