The Dallas-Fort Worth-Arlington metropolitan area’s 146,000-population increase last year was the most of any metro area, and Maricopa County, Ariz., saw a population increase of nearly 74,000 — the most of any county last year — according to the U.S. Census Bureau’s July 1, 2017, population estimates released in March, 2018.
According to their estimates we get a detailed picture of the largest growth areas in the United States… And also the ones that are declining in population.
Among the nation’s counties, the top 10 with the largest numeric growth are all located in the South and the West. The 10 largest counties in the country all maintained their rank compared to last year.
Here are some of the statistics from their website [Source: U.S. Census Bureau].