Ashland is a city in the U.S. state of Ohio and the county seat of Ashland County. The population was 20,362 at the 2010 census. It is the center of the Ashland Micropolitan Statistical Area (as defined by the United States Census Bureau in 2003). Ashland is well known in the state for its "welcome sign" that proclaims the city to be "The World Headquarters of Nice People."Ashland was designated a Tree City USA by the National Arbor Day Foundation.