Meridian is a city in the U.S. state of Idaho, in Ada County. The Meridian population is more than 106,800, making it the third largest city after Boise and Nampa in Idaho. The total area of the city is 26,84 square kilometers, 69,52 of which 26,79 square kilometers are land and 0,05 square kilometers are water. Most Meridian lies on a flat plain, roughly in the Treasure Valley's central north. A small bench lies along the city's south east side. Several irrigation canals cross the city, which usually run from the southeast to the northwest. The Boise River flows north of town.