Hidalgo County (/hɪˈdælɡoʊ/; Spanish pronunciation: [iˈðalɣo]) is located in the U.S. state of Texas. As of the 2024 census estimate, its population was 914,820, making it the ninth-most populous county in Texas, and the most populous county outside of the counties in the Texas Triangle. However, based on housing permits and service usage, county officials believe the true population is around 1.2 million, if 'a full and accurate census count is completed.' 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. It is located in the Rio Grande Valley of South Texas and is one of the fastest-growing counties in the United States. Hidalgo County is designated by the U.S. Census Bureau as the McAllen–Edinburg–Mission metropolitan statistical area, which itself is part of the McAllen-Edinburg-Mission-Rio Grande City, Texas combined statistical area with neighboring Starr County.
With a population that is 91.9% Hispanic as of 2020, it is Texas' second-most populous majority-Hispanic county and the fifth-largest nationwide. It is also the largest county which is over 90% Hispanic. It is also the southernmost landlocked county in the United States, and in 2021, it was the largest county in the nation with a total fertility rate above the replacement level (at 2.13).