The Municipality of Dumingag is located in the eastern portion of the Province of Zamboanga del Sur, and is known as one of the "Eastern Municipalities". Its is located in the North West portion of the Salug Valley and is bounded on the east by the Municipality of Mahayag; on the north by the Municipality of Sergio Osmeña; on the west by Siayan, a municipality of Zamboanga del Norte, and on the south by the Municiapality of Don Mariano Marcos, now Sominot. Bounded on the north (latitude 8 degrees, 20 minutes and 00 seconds); by the Municipality of Sergio Osmeña, Province of Zamboanga del Norte, on the east, (longitude 123 degrees, 22 minutes and 57.18 seconds) by the Municiapality of Mahayag, Province of Zamboanga del Sur, on the south by (latitude 8 degrees, 06 minutes and 17.68 seconds) by the Municipalities of Midsalip and Don Mariano Marcos (now Sominot), Province of Zamboanga del Sur; and on the west, (longitude 123.10 degrees and 00 seconds) by Municipality of Siayan, Province of Zamboanga del Norte.



Topography



The topography of Dumingag can be classified as 50% relatively rugged areas and the other half represents the lowlands, rolling hills and plateaus. The lowland comprise 9.41% of the total land area. These lowland reserves form part of the scenic Salug Valley.



Water Bodies



Dumingag is traversed by 5 principal rivers namely: Dekayo river in the Northern portion moving towards the Municipalit of Sergio Osmeña and Ecuan river on the South Western portion, moving towards the Municipality of Sindangan, both municipalities of Zamboanga del Norte. The rest of the rivers are Timonan river which originates from the ridge of Mt. Paraya, an area of Barangay Sinonok. These three rivers wound out to form into one at the South Eastern part of the municipality known as Dipolo river, the main tributary water body of Salug Valley.



Climate



Rainfall

The regions of Dumingag has basically two types of climate. The northern portion of the municipality basically comprised of mountain ranges has a quarter of dry season with less than 75 mm. rainfall per month. The central and southern portion, which form part of the Salug Valley, have most of the months covered by 75 mm. rainfall and even greater during the last quarter of the year. The latest impact of the El Niño phenomenon has considerably changed the rainfall pattern within Salug Valley, the next survey may reflect the actual change it had imparted.

Temperature

Dumingag has an invigorating climate which is neither so hot nor so cold. The mean annual temperature for one year as recorded by the PAGASA in Dipolog City shows 27.4 degrees as the average temperature. The cold months are from January to December registering a mean temperature of 26.7 & 26.8 degrees respectively. The highest temperature recorded is for the month of May with 36.6 degrees celcius while the extreme is on December with 17.4 degrees celcius. However, the El Niño Phenomenon has considerably changed the temperature pattern of Salug Valley Zone, its impact may be reflected in the succeeding surveys.

Typhoons

Dumingag, unlike most coastal towns is seldom hit by typhoons due to the natural protective mountain ranges blocking the strong winds from the sea. Mt. Malindang is on the east is a good barrier and the different mountain ranges such as Mt. Dapiwak on the North, Midsalip on the South, Siayan on the West equally protect the Municipality from ravaging typhoons.

Ethnic Groups & Mother Tongue

The 1990 Census of Population revealed that 26,497 inhabitants of the place are Cebuanos while 4,707 are Subanens and the rest of about 6.89% are distributed among different ethnic origins.