Sierra Vista is a city in Cochise County, Arizona, United States. According to the 2020 Census, the population of the city is 45,308, and is the 27th most populous city in Arizona. The city is part of the Sierra Vista-Douglas Metropolitan Area, with a 2010 population of 131,346. Fort Huachuca, a U.S. Army post, has been incorporated and is located in the northwest part of the city. Sierra Vista is bordered by the cities of Huachuca City and Whetstone to the north and Sierra Vista Southeast to the South.

Cochise County is a county in the southeastern corner of the U.S. state of Arizona. It is named after Cochise, a Chiricahua Apache who was a key war leader during the Apache Wars.