Births, immigration and migration from other states helped make Dallas-Fort Worth and Houston two of the country's fastest-growing metro areas.
Details were released yesterday by the Census Bureau.
The population of the Dallas-Fort Worth area grew by more than 842,000, topping 16 percent, from 2000 to 2006.
It's the second-largest numerical increase of the 361 metro areas studied.
Houston, which was ranked third, gained nearly 825,000 people, or 17 and a-half percent.
Authorities say about half of the growth in the two metro areas is coming from births.
The rest is due to new immigrants or people moving from other regions of the U.S.
Austin and San Antonio also ranked among the country's top 20 in population growth during the decade.