Population of Sierra Vista, AZ Last official estimated population of Sierra Vista city (Cochise County**, Arizona state) was 43,806 (year 2014) [1]. This was 0.014% of total US population and 0.64% of total Arizona state population. Area of Sierra Vista city is 152.7 miÂ² (=395.4 kmÂ²) [6], in this year population density was 286.94 p/miÂ². If population growth rate would be same as in period 2010-2014 (-0.05%/yr), Sierra Vista city population in 2018 would be 43,724*.