Hidalgo County is located in the U.S. state of Texas. As of the 2020 census, its population was 870,781, making it the ninth-most populous county in Texas, and the most populous county outside of the counties in the Texas Triangle. The county seat is Edinburg and the largest city is McAllen. The county is named for Miguel Hidalgo y Costilla, the priest who raised the call for Mexico's independence from Spain.