The Municipality of Catarman is located at the center of the Northernmost part of Samar Island, beautifully surrounded by white sandy beaches. It is bounded on the north by the Philippine Sea, on the west by the Municipality of Bobon, on the east by the Municipality of Mondragon, and on the south by the Municipality of Lope de Vega. There are at present 55 barangays; 15 of them are in the poblacion, and 22 barangays are considered urban and within its relatively large Municipal Jurisdiction. Catarman is located at 124°38'00'' East Longitude and 12°30'30'' North Latitude.

Catarman has a total land area of 46,443 hectares with 55 barangays.

On the Pacific coast are flat lowlands with the interior characterized by outlying low hills. Mount Puyao in Barangay Liberty is the highest peak in the sea. The Catarman River, a major provincial river, divides the eastern and the western parts of the town. It is fed by the Paticua, Hibulwangan, Mahangna, Tura, Danao and Maroyondoyon creeks together with lesser prominent estuaries.

The Municipality of Catarman is politically subdivided into 55 barangays, 22 is in the urban area and 33 barangays are covering rural area.