Calvillo (Spanish: [kalˈβiʝo]) is a city in the Mexican state of Aguascalientes. The town serves as the municipal seat of the surrounding municipality of Calvillo. Calvillo is the second most populated city in the state, surpassed in importance only by the capital city. It is located about 52 kilometers from the city of Aguascalientes. It stands at 21°51′N 102°43′W / 21.850°N 102.717°W in the southwestern corner of the state.