what county is sierra vista az
For places in California, see Sierra Vista, California (disambiguation). Sierra Vista is a city in Cochise County, Arizona, United States. As of the 2010 census the population of the city was 43,888. 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, is located in the northwest part of the city.