Sponsored Topics. Lennox is a city in Lincoln County, South Dakota, United States. The population was 2,111 at the 2010 census. The city was named for Ben Lennox, a railroad official. Lennox is located at 43°21′14″N 96°53′44″W / 43.35389°N 96.89556°W / 43.35389; -96.89556 (43.353769, -96.895489).