Mombetsu is located in the northeast of Hokkaido, the northernmost area of japan. its north latitude ranges from  43K59' (facing the Sea of Okhotsk) to 44K24', and its east longitude from 143K5' to 143K34'. The shoreline spreads to the southeast in the shape of a bow. Its harbors are important not only to Hokkaido but also to japan. The habors are surrounded by gently sloping mountains and farmlands cover the region.

From east to west: 34.1km 
From south to north: 40.6km

(Number of households: 11,670)

The name Mombetsu derives from "Moupetto" (calm river), a word of aboriginal Ainus of Hokkaido. The municipality adopted the name "Mombetsu" in 1869.

Although Mombetsu's climate is usually gentle - characteristic of the Okhotsk Oceanic climate - it is very cold in winter largely because drift ice moving south from Siberia touches its shores. In summer, the temperature sometimes exceeds  30KC  due  to the Foehn phenomenon of the western wind. With an average temperature of  18.3KC  in August and - 6.9KC  in Feburuary, the annual average temperature is  5.9KC. Precipitation is less then in other parts of Hokkaido: The total annual amount is 888 mm and the deepest snow measures approximately 1 m to 1.2m. The annual duration of sunshine is 1,824 hours, representing a percentage of possible annual sunshine of 41%.

The indigenous Ainu and other peoples lived in Hokkaido in ancient times, and later the wajin (japanese) advanced into this is land and engaged in fishing. During the Meiji era (1868-1921), many people came from the mainland of Honshu and settled in Mombetsu as a result of full-scale political and economic reforms, and they engaged actively in agriculture in addition to the existing fishing industry. A village office was established in Mombetsu in 1889 and thus a modern administrative system was initiated in the Mombetsu district. In 1930, a vain of gold \ the largest of its kind in the Orient \ was discovered in Konomai, Mombetsu, and this vein greatly benefited the economy of Mombetsu for the ensuing 40 years. On july 1, 1954, Mombetsu town, Shokotsu village and Kami-Shokotsu village were consolidated and reorganized as the city of Mombetsu with a population of 36,000 Mombetsu has maintained steady growth since. With its "City Project for internaional Drift Ice Research" which seeks to create an enriched local community, Mombetsu is now steadily developing as an international city pioneering the future of the Okhotsk region.