Plano is a city in the U.S. state of Texas. 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. Plano is located north of Dallas and within Collin County. It is the largest of the county. Plano is also one of the principal cities of the Dallas-Fort Worth metropolitan area.