The building where government affairs were mainly carried out was called "Seicho" (government office) in the province under the Ritsuryo system, county and "Josaku" (government office with defense system), therefore, Kokucho was often called Seicho as well.
令制国、郡、城柵で政務の中心となる建物をまとめて政庁というので、国庁もしばしば政庁と呼ばれる。