Noonan is a city in Divide County, North Dakota, United States. The population was 137 at the 2020 census. Noonan was founded in 190…Noonan is a city in Divide County, North Dakota, United States. The population was 137 at the 2020 census. Noonan was founded in 1907 and named after a family that had business, farm, and coal interests in the area. It was once known as "The White City" because of an ordinance requiring all buildings to be painted white.