Bankston is a city in Dubuque County, Iowa, United States. It is part of the 'Dubuque, Iowa Metropolitan Statistical Area'. The population was 2…Bankston is a city in Dubuque County, Iowa, United States. It is part of the 'Dubuque, Iowa Metropolitan Statistical Area'. The population was 23 at the 2020 census, down from 27 in 2000.