Plano is a city in the U.S. state of Texas, where it is the largest city in Collin County. Plano is also one of the principal cities of the Dallas-Fort Worth metropolitan area. With a population of 285,494 at the 2020 census, it is the ninth most-populous city in Texas, and, respectively, the 72nd most populous city in the United States.

Collin County is located in the U.S. state of Texas. It is part of the Dallas-Fort Worth-Arlington metropolitan statistical area, and a small portion of the city of Dallas is in the county. At the 2020 United States census, the county's population is 1,064,465, making it the sixth-most populous county in Texas and the 43rd-largest county by population in the United States. Its county seat is McKinney.