Davis City is a city in Decatur County, Iowa, United States. The population was 179 at the time of the 2020 census. Davis City was laid out in 18…Davis City is a city in Decatur County, Iowa, United States. The population was 179 at the time of the 2020 census. Davis City was laid out in 1855. It is named for William Davis, who operated a sawmill. Davis City was a shipping point on the Chicago, Burlington and Quincy Railroad.