Hesston is a city in Harvey County, Kansas, United States. As of the 2020 census, the population of the city was 3,505. Large manufacturing facilities for AGCO and Excel Industries are located in Hessto…Hesston is a city in Harvey County, Kansas, United States. As of the 2020 census, the population of the city was 3,505. Large manufacturing facilities for AGCO and Excel Industries are located in Hesston. It is home of Hesston College.