Kettering is a city in Montgomery County, Ohio, United States. It is an inner suburb of Dayton. As of the 2020 census, the city had a populat…Kettering is a city in Montgomery County, Ohio, United States. It is an inner suburb of Dayton. As of the 2020 census, the city had a population of 57,862, making it the most populous suburb in the Dayton metropolitan area.