Dayton is the sixth largest city in the U.S. state of Ohio and is the county seat of Montgomery County. In the 2010 census, the population was 141,527; the Dayton metropolitan area had 841,502 residents, making it the fourth largest metropolitan area in Ohio and the sixty-first largest in the United States. The Dayton-Springfield-Greenville Combined Statistical Area had a population of 1,080,044 in 2010 and is the 43rd largest in the United States. Dayton is situated within the Miami Valley region of Ohio just north of the Cincinnati–Northern Kentucky metropolitan area.