Civil government in Romblon was established under the Americans on 16 March 1901. Magallanes was one of 11 new municipalities. In 1917, due to reorganization and the province's difficult financial status as a newly restored entity, the former municipality of Magallanes was abolished and annexed to Cajidiocan. It was only restored to its independent municipality status on 1 March 1933, with the new name Magdiwang, in honor of the Magdiwang faction of the Philippine revolutionary group, Katipunan. It was inaugurated through festivities which lasted from 24 to 25 March 1933 and led by Governor Manuel T. Alvero.