Ferguson is a city in Marshall County, Iowa, United States. The population was 97 at the time of the 2020 census. Ferguson was founded in 188…Ferguson is a city in Marshall County, Iowa, United States. The population was 97 at the time of the 2020 census. Ferguson was founded in 1882. Ferguson is located at 41°56′15″N 92°51′54″W / 41.93750°N 92.86500°W.