I always thought DFW was in the top 10 of largest metropolotan areas, but I guess I was wrong. People always think Ft Worth is larger than it really is, but it's actually a small fraction of the metroplex, whereas Dallas holds well over the majority of the population. Granted, Ft Worth had the largest amount of growth last year, by 21,500 and percentage growth is high, but percentage growth is only high because the original population count was low.
For all of Tarrant County, the population is 1,702,250.
For all of Dallas County, the population is 2,383,300.
For the main counties in between, you have Collin County at 690,500 and Denton County at 578,500.
Overall, the ranking for the largest metropolotan area encompasses 16 counties.
The entire artice can be found here.