Zumarraga is divided into 25 barangays.
The present-day town Zumarraga in Buad Island was called Buad in earlier days. Before 1768, The Jesuits had established a visita on the island of Buad southwest of Catbalogan. In 1845, The Franciscan Fray Martín de Yepes built a church of wood planks.
On 13 March 1863, Buad was created as a new town and given a new name, Zumarraga, then on 12 October 1865, Buad parish was created by separating it from Catbalogan in accordance with a decree of 13 March 1863.