Humansville is a city in Polk County, Missouri, United States. As of the 2020 census, the city population was 907. Humansville was named a…Humansville is a city in Polk County, Missouri, United States. As of the 2020 census, the city population was 907. Humansville was named after an American settler, Judge James G. Human, who settled in the area in 1834. A post office called Humansville has been in operation since 1839.