High Quality Content by WIKIPEDIA articles! Moraine is a city in Montgomery County, Ohio, United States. The population was 6,307 at the 2010 census. The city is part of the The Dayton Metropolitan Statistical Area, which includes Montgomery county. Moraine, as part of the Dayton area, is situated within the Miami Valley region of Ohio, just north of the Cincinnati metropolitan area. The city is also home to the outdoor waterpark Splash Moraine.