Meridian is the second-largest city in Ada County, Idaho, USA, and the third-largest in the state. As of 2010, the population of Meridian was 75092. Having recently surpassed the eastern Idaho cities of Pocatello and Idaho Falls, the 2010 census placed Meridian as the third-largest city in Idaho behind Boise and Nampa, all in the Treasure Valley. Meridian is the state's fastest-growing city, with an 81.5 percent increase in population since 2000. The Meridian School District is the largest in the state. Meridian is part of the Boise metropolitan area.