Akagi Shrine, Shinto shrine near a lake on Mount Akagi, Gunma Prefecture, Japan

Akagi Shrine is a Shinto shrine on Kotori-ga-shima islet in Lake Ono (Onuma) on Mount Akagi, Gunma Prefecture. Its present site dates from 1970, when the shrine was moved from the old Dōdō grounds on the lake's south shore and rebuilt. The main hall enshrines Akagi Daimyōjin, Ōkuninushi, Iwa-tsutsunoo, Iwa-tsutsuhime, Futsunushi and Toyoki-irihiko, with Tokugawa Ieyasu, Ōyamakui and Takeminakata in the auxiliary hall.

The shrine's founding date is unknown; tradition credits Toyoki Irihiko no Mikoto with worshipping the mountain and lake spirits, and halls were built under Emperors Ingyo and Yomei. In 806 it was moved to the south shore of Lake Ono, and the era name Daido gave the site its common name, Daido Akagi Shrine. In 1601 Sakai Shigetada, lord of Maebashi Castle, restored the halls, and Sakai Tadatoyo later enshrined Tokugawa Ieyasu beside the main deities.

The shrine's name Akagi comes from the mountain it serves, and its formal title is Akagi Shrine, though it is often called Daidō Akagi Shrine after the old site. The main deities are Akagi Daimyōjin and Toyoki Iribiko no Mikoto, with Ōkuninushi and others also enshrined. The annual Yama-biraki festival on April 8 and the June 1 Kamimiso rite are among the observances held here.

The shrine stands at 4-2 Akagisan, Fujimi-machi, Maebashi, Gunma. From JR Maebashi Station take a Kan'etsu Kotsu bus to the Akagi Hiroba-mae stop, about 1 hour 10 minutes, then walk roughly 5 minutes. The grounds were moved to Kotorigashima in 1970, so the present precinct is compact and easy to cross on foot.

The shrine's present site on Kotorigashima was chosen in 1970, when the shrine was moved from its old Odo grounds; the move drew protests over damage to the island's setting. Beneath the island lies the Kotorigashima site, where a 1372 ho-to pagoda contained a sutra container and ten mirrors, now a Gunma Prefectural cultural property.