Menno is a city in Hutchinson County, South Dakota, United States. The population was 614 at the 2020 census. Menno was laid out in 1879. …Menno is a city in Hutchinson County, South Dakota, United States. The population was 614 at the 2020 census. Menno was laid out in 1879. According to the United States Census Bureau, the city has a total area of 0.52 square miles, all land.