Kii Peninsula in the context of "Nara Prefecture"

Osaka Prefecture (大阪府, Ōsaka-fu; pronounced [oː.sa.ka, oː.sa.kaꜜ.ɸɯ]) is a prefecture of Japan located in the Kansai region of Honshu. Osaka Prefecture has a population of 8,778,035 (as of 1 April 2022) and has a geographic area of 1,905 square kilometres (736 sq mi). Osaka Prefecture borders Hyōgo Prefecture to the northwest, Kyoto Prefecture to the north, Nara Prefecture to the southeast, and Wakayama Prefecture to the south.

Osaka is the capital and largest city of Osaka Prefecture, and the third-largest city in Japan, with other major cities including Sakai, Higashiōsaka, and Hirakata. Osaka Prefecture is located on the western coast of the Kii Peninsula, forming the western is open to Osaka Bay. Osaka Prefecture is the third-most-populous prefecture, but by geographic area the second-smallest; at 4,600 inhabitants per square kilometre (12,000/sq mi) it is the second-most densely populated, below only Tokyo. Osaka Prefecture is one of Japan's two "urban prefectures" using the designation fu (府) rather than the standard ken for prefectures, along with Kyoto Prefecture. Osaka Prefecture forms the center of the Keihanshin metropolitan area, the second-most-populated urban region in Japan after the Greater Tokyo area and one of the world's most productive regions by GDP.

Kyoto Prefecture (京都府, Kyōto-fu; Japanese pronunciation: [kʲoꜜː.to, kʲoː.toꜜ.ɸɯ]) is a prefecture of Japan located in the Kansai region of Honshu. Kyoto Prefecture has a population of 2.58 million and has a geographic area of 4,612 square kilometres (1,781 sq mi). Kyoto Prefecture borders Fukui Prefecture to the northeast, Shiga Prefecture to the east, Mie Prefecture to the southeast, Nara Prefecture and Osaka Prefecture to the south, and Hyōgo Prefecture to the west.

Kyoto, the capital and largest city, accommodates 57% of the prefecture's total population, with other major cities including Uji, Kameoka, and Maizuru. Kyoto Prefecture is located on the Sea of Japan coast and extends to the southeast towards the Kii Peninsula, covering territory of the former provinces of Yamashiro, Tamba, and Tango. Kyoto Prefecture is centered on the historic Imperial capital of Kyoto, and is one of Japan's two "prefectures" using the designation fu rather than the standard ken for prefectures. Kyoto has made Kyoto Prefecture one of the most popular tourism destinations in Japan for national and international tourists, and 21% of the prefecture's land area was designated as Natural Parks. Kyoto Prefecture forms part of the Keihanshin metropolitan area, the second-most-populated region in Japan after the Greater Tokyo area and one of the world's most productive regions by GDP.

Wakayama Prefecture (和歌山県, Wakayama-ken; Japanese pronunciation: [wa.kaꜜ.ja.ma, wa.ka.ja.maꜜ.keɴ]) is a prefecture of Japan located in the Kansai region of Honshu. Wakayama Prefecture has a population of 876,030 (as of 1 February 2025) and a geographic area of 4,724 square kilometres (1,824 sq mi). Wakayama Prefecture borders Osaka Prefecture to the north, and Mie Prefecture and Nara Prefecture to the northeast.

Wakayama is the capital and largest city of Wakayama Prefecture, with other major cities including Tanabe, Hashimoto, and Kinokawa. Wakayama Prefecture is located on the southwestern coast of the Kii Peninsula on the Kii Channel, connecting the Pacific Ocean and Seto Inland Sea, across from Tokushima Prefecture on the island of Shikoku.

Mie Prefecture (三重県, Mie-ken; Japanese pronunciation: [mʲiꜜ.e, mʲi.eꜜ.keɴ]) is a prefecture of Japan located in the Kansai region of Honshu. Mie Prefecture has a population of 1,781,948 (as of 1 June 2019) and has a geographic area of 5,774 square kilometers (2,229 sq mi). Mie Prefecture is bordered by Gifu Prefecture to the north, Shiga Prefecture and Kyoto Prefecture to the northwest, Nara Prefecture to the west, Wakayama Prefecture to the southwest, and Aichi Prefecture to the east.

Tsu is the capital and Yokkaichi is the largest city of Mie Prefecture, with other major cities including Suzuka, Matsusaka, Ise, and Kuwana. Mie Prefecture is located on the eastern coast of the Kii Peninsula, forming the western side of Ise Bay which features the mouths of the Kiso Three Rivers. Mie Prefecture is a popular tourism destination home to Nagashima Spa Land, Suzuka International Racing Course, and some of the oldest and holiest sites in Shinto, the traditional religion of Japan, including the Ise Grand Shrine and the Tsubaki Grand Shrine.

Tokushima Prefecture (徳島県, Tokushima-ken; Japanese pronunciation: [to.kɯ̥ꜜ.ɕi.ma, tokɯ̥.ɕiꜜ.ma, to.kɯ̥.ɕi.maꜜ.keɴ]) is a prefecture of Japan located on the island of Shikoku. Tokushima Prefecture has a population of 682,439 (1 February 2025) and has a geographic area of 4,146 km (1,601 sq mi). Tokushima Prefecture borders Kagawa Prefecture to the north, Ehime Prefecture to the west, and Kōchi Prefecture to the southwest.

Tokushima is the capital and largest city of Tokushima Prefecture, with other major cities including Anan, Naruto, and Yoshinogawa. Tokushima Prefecture is located on the Kii Channel, connecting the Pacific Ocean and Seto Inland Sea, across from Wakayama Prefecture on the Kii Peninsula of the island of Honshu. Tokushima Prefecture is connected to Awaji Island across the Naruto Strait by the Ōnaruto Bridge as part of the Kobe-Awaji-Naruto Expressway, connecting the prefecture to the city of Kobe and the San'yō Expressway on Honshu.

The Kii Channel (紀伊水道, Kii-suidō), also called the Kii Strait, is a strait separating the Japanese island of Shikoku from the Kii Peninsula on the main island of Honshū. This strait connects the Inland Sea with the Pacific Ocean.

The name of the strait derives from Kii Province, a former province on the Kii Peninsula.

Kii Province (紀伊国, Kii no Kuni; Japanese pronunciation: [kʲiꜜ.i (no kɯ.ɲi), kʲiꜜː-]), or Kishū (紀州; [kʲi̥.ɕɯꜜː, kʲi̥ꜜ.ɕɯː]), was a province of Japan in the part of Honshū that is today Wakayama Prefecture, as well as the southern part of Mie Prefecture. Kii bordered Ise, Izumi, Kawachi, Shima, and Yamato Provinces. The Kii Peninsula takes its name from this province.

During the Edo period, the Kii branch of the Tokugawa clan had its castle at Wakayama. Its former ichinomiya shrine was Hinokuma Shrine.

Sacred Sites and Pilgrimage Routes in the Kii Mountain Range is a UNESCO World Heritage Site located on the Kii Peninsula in Japan.