Collin County hit the 1 million-resident mark in 2018, according to the latest U.S. Census Bureau estimates released April 18. Collin County added 33,753 residents from 2017-18, making it the fourth-fastest-growing county in the country. Harris County was the No. 3 fastest-growing county from 2017-18, followed by Clark County, Nevada, at No. 2 and Maricopa County, Arizona, at No. 1. Collin County’s growth last year included 27,277 new residents moving into the area—of which 5,482 came from outside the U.S. and 21,795 relocated domestically. Out of 3,142 counties in the nation, 52.2% showed positive total net migration in 2018, meaning more people moved into the county than moved out, according to a Census press release. “One interesting trend we are seeing this year is that metro areas not among the most populous ... are ranked in the top 10 for population growth,” said Sandra Johnson, a demographer in the U.S. Census Bureau’s Population Division, in the press release. The Dallas-Fort Worth-Arlington and Houston-The Woodlands-Sugar Land metro areas each gained over 1 million people since 2010, according to 2018 population estimates. With populations of 7.5 million and 7 million, respectively, the Dallas-Fort Worth-Arlington and Houston-The Woodlands-Sugar Land metro areas are ranked the fourth and fifth most-populous metros behind New York, Los Angeles and Chicago. The state’s overall population grew by over 3.5 million residents from mid-2010 to July 2018, according to the Census, for a total of 28.7 million residents.