Dayton is the sixth-largest city in the state of Ohio and is the county seat of Montgomery County. A small portion of the city extends into Greene County. In the 2010 census, the population was 141,759, and the Dayton metropolitan area had 799,232 residents, making it Ohio's fourth-largest metropolitan area, after Cleveland, Cincinnati, and Columbus and the 63rd-largest in the United States. The Dayton-Springfield-Greenville Combined Statistical Area had a population of 1,080,044 in 2010, making it the 43rd-largest in the United States. Dayton is within Ohio's Miami Valley region, just north of the Cincinnati–Northern Kentucky metropolitan area.Ohio's borders are within 500 miles of roughly 60 percent of the country's population and manufacturing infrastructure, making the Dayton area a logistical centroid for manufacturers, suppliers, and shippers.