Mission is a city in Hidalgo County, in the US state of Texas, United States. The population was 85,778 at the 2020 census and an estima…Mission is a city in Hidalgo County, in the US state of Texas, United States. The population was 85,778 at the 2020 census and an estimated 86,635 in 2022. Mission is part of the McAllen–Edinburg–Mission and Reynosa–McAllen metropolitan areas.