is 334 meters high and is also called "Gagyu (lying down) Mountain" because of its appearance "like a cow lying down. It was used as a fortress from the Meiji era (1868-1912) until 1945 and was off-limits, and traces of war, such as gun emplacements, still remain.

Mount Hakodate was a volcanic island created by prehistoric volcanic activity. Earth and sand accumulated and formed a sandbar, which was connected to Hokkaido (Kameda Peninsula) approximately 5,000 years ago, resulting in the current topography of Hakodate (landlocked island).

Designated as a special protection area for birds and animals in 1964.

The mountain is made up of a chain of 12 mountains, and is called "Gagyuzan" (literally "lying cow mountain") because of its appearance like a cow lying down. The observatory at the top of the mountain offers a miraculous night view, and a mountain climbing route has been developed at the foot of the mountain, allowing visitors to enjoy nature and scenery while hiking the mountain. Maps and other climbing information are available at the Mt. Hakodate Fureai Center, the starting point of the trail.