GUASTALLA, a walled town of Northern Italy, duchy of Modena, capital of a small district of the same name, on the right bank of the Po, 16 miles N. of Reggio. It is the see of a bishop, and has a cathedral and several other churches, and a public library. Manufactures—chiefly silk fabrics and twist. The French defeated the Imperialists under its walls in 1734. Pop. 10,000. The district of Guastalla formerly belonged to Parma, but since the death of the empress Maria Louisa it has been transferred to Modena.