Mount Mekunnai, Andesitic volcano in Shiribeshi Subprefecture, Japan.

Mount Mekunnai is an andesitic volcano in Shiribeshi Subprefecture that rises to approximately 1,220 meters as part of the Mount Raiden Volcanic Group. The summit features steep slopes with rocky exposed surfaces and sharp terrain throughout the upper reaches.

Mount Mekunnai is a stratovolcano that was active between about 2 million and 500,000 years ago, in the Pleistocene. Within the Niseko Range it belongs to the older generation of volcanoes. Its summit, 1,220 m high, lies southeast of the 1,202.3 m third-order triangulation point named Shikoku-nai.

The name comes from the Mekunnai River, whose source lies on the mountain; in Ainu, mak-un-nay means "the stream behind the mountain". The peak is listed among the Hokkaido Hundred Mountains, and hot springs emerge on its middle slope in the Shinmi district of Rankoshi, where two hot-spring inns stand.

The mountain is accessible via hiking trails during spring and summer months, with local mountaineering centers offering experienced guides for ascents. Visitors should prepare for changing mountain weather and bring warm clothing, as conditions at higher elevations can shift quickly.

The summit's highest point lies southeast of the third-order triangulation station named "Shikokunai", whose spot height of 1,202.3 m was remeasured by the Geospatial Information Authority of Japan in 2014, while the true summit stands at 1,220 m. The mountain also has several tiny ponds, most of them on a small terrace on the southern foot.