McAllen is a city in the U.S. state of Texas and the most populous city in Hidalgo County. It is located at the southern tip of the state in the Rio Grande Valley, on the Mexico–United States border. The city limits extend south to the Rio Grande, across from the Mexican city of Reynosa. McAllen is about 70 mi west of the Gulf of Mexico. As of the 2020 census, McAllen's population was 142,210, making it the 23rd-most populous city in Texas.