By Mindi V.
Collin County is a county located in the U.S. state of Texas. As of the 2010 United States Census, the county's population was 782,341, making it the seventh-most populous county in Texas and the 63rd largest county by population in the United States. Its county seat is McKinney.
Collin County is part of the Dallas-Fort Worth-Arlington, TX Metropolitan Statistical Area. A small portion of the city of Dallas is located in the county.