McKinney is a city in and the county seat of Collin County, Texas, United States. It is Collin County's third-largest city, after Plano and Frisco. A suburb of the Dallas–Fort Worth metroplex, McKinney is about 32 miles (51 km) north of Dallas.

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.