The Oshima Peninsula (渡島半島 ''Oshima-hantō'') is the

south South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

ernmost part of

Hokkaidō is the second-largest island of Japan and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by railway via the Seikan Tunnel. The ...

, the northernmost of the

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

ese

island An island or isle is a piece of land, distinct from a continent, completely surrounded by water. There are continental islands, which were formed by being split from a continent by plate tectonics, and oceanic islands, which have never been ...

s. Where the peninsula starts is open to interpretation. A more generous interpretation is to draw a line southeast from Ishikari Bay across the Ishikari Plain to

Yūfutsu District, Hokkaido is a district divided between Iburi and Kamikawa Subprefectures in Hokkaido, Japan. Towns and villages Iburi Subprefecture * Abira (merger of Hayakita and Oiwake) * Atsuma * Mukawa Kamikawa Subprefecture * Shimukappu History *1869 - With t ...

. A narrower interpretation is to draw a line connecting Suttsu on the

Sea of Japan The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it ...

and Oshamambe on

Uchiura Bay The or is a bay southeast of the island of Hokkaido in northern Japan. It has also been known as Iburi Bay and Volcano Bay. History The shoreline of Uchiura Bay was first settled by the Jōmon people as early as 4000 BC. Trade settlements have ...

. This narrow interpretation encompasses the subprefectures of Oshima and Hiyama. At its southern end it forks into the southwest-pointing Matsumae Peninsula and the southeast-pointing Kameda Peninsula. These two peninsulas face Tsugaru and

Shimokita Peninsula The is the remote northeastern cape of the Japanese island of Honshū, stretching out towards Hokkaido. Overview It is bordered by the Pacific Ocean to the east, Tsugaru Strait to the north and Mutsu Bay to the west and south. Shaped like an ...

s of

Honshū , historically known as , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the seventh-largest island in the world, and the second-most populous after the Indonesian ...

across the

Tsugaru Strait The is a strait between Honshu and Hokkaido in northern Japan connecting the Sea of Japan with the Pacific Ocean. It was named after the western part of Aomori Prefecture. The Seikan Tunnel passes under it at its narrowest point 12.1 miles ...

. The

Ōnuma Quasi-National Park is a quasi-national park on the Oshima Peninsula in southwest Hokkaidō, Japan. The park encompasses the volcanic as well as the and ponds, which abut against the west slope of the mountain. The park, which was designated as quasi-national ...

is located on the peninsula. The terrain of the peninsula is mountainous, with settlements mostly located in flat, lowland areas. Oshima Peninsula is home to several active

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

es such as

Mount E is an active stratovolcano of the Kameda peninsula, which is itself part of the larger Oshima Peninsula. It is in the rural, eastern region of Hakodate, Hokkaido, Japan. Mount E is part of Esan Prefectural Natural Park. Geology Mount E co ...

and

Hokkaido Koma-ga-take , also , , or just is a andesitic stratovolcano on the border between Mori, Shikabe, and Nanae, all within the Oshima Subprefecture of Hokkaidō, Japan. Occurrence of volcanic activity started some 30,000 years ago. Following roughly 5,000 ...

. The area also contains several

onsen In Japan, are hot springs and the bathing facilities and Ryokan (inn), traditional inns around them. There are approximately 25,000 hot spring sources throughout Japan, and approximately 3,000 ''onsen'' establishments use naturally hot water ...

hot springs. The peninsula is home to two cities:

Hakodate is a Cities of Japan, city and seaports of Japan, port located in Oshima Subprefecture, Hokkaido, Japan. It is the capital city of Oshima Subprefecture. As of January 31, 2024, the city had an estimated population of 239,813 with 138,807 househol ...

and the smaller adjacent Hokuto, as well as numerous small fishing and agricultural towns.

Matsumae Castle is a castle located in Matsumae, Hokkaido, Japan, and is the northernmost castle in Japan. The only traditional style Edo period castle in Hokkaidō, it was the chief residence of the '' han'' (estate) of the Matsumae clan. History First built i ...

, the northernmost castle in Japan and only castle on the island of Hokkaido, is located on the Oshima peninsula. The climate is

humid continental Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

(''Dfa''/''Dfb'') except along the coast of the Matsumae Peninsula where it is

oceanic Oceanic may refer to: *Of or relating to the ocean *Of or relating to Oceania **Oceanic climate **Oceanic languages **Oceanic person or people, also called "Pacific Islander(s)" Places * Oceanic, British Columbia, a settlement on Smith Island, ...

(''Cfb'',) The

hardiness zone A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most widely ...

is high for an east-coast Northern Hemisphere location at such a latitude and ranges up to 8b on the Matsumae.

Ecology

Oshima Peninsula is separated from the rest of the island of Hokkaido by the Kuromatsunai Depression - an area of intensive agricultural development that forms a natural, northern boundary to the area. The peninsula has an active

Ussuri brown bear The Ussuri brown bear (''Ursus arctos lasiotus''), also known as the Ezo brown bear, Russian grizzly bear, or the black grizzly bear, is a subspecies of the brown bear or a population of the Eurasian brown bear (''U. a. arctos''). One of the lar ...

population, which have historically caused major damages to livestock and crops, and thus have been indiscriminately hunted for over 120 years.

References

Peninsulas of Hokkaido {{Hokkaido-geo-stub