Peosta is a city in Dubuque County, Iowa, United States, and an exurb of the city of Dubuque. It is part of the Dubuque, Iowa Metropolitan Statistical Area. The population was 1,908 in the 2020 census, an increase of 193% from 651 in 2000. Peosta experienced a 70% increase in population from 2000 to 2007, making it the state's 10th fastest-growing city during that period.