Tōeizan Kan'ei-ji Endon-in is a Tendai Buddhist temple in Tokyo, Japan, founded in 1625 during the Kan'ei era by Tenkai, in an attempt to emulate the powerful religious center Enryaku-ji, in Kyoto. The main object of worship is Yakushirurikō Nyorai.
It was named in a reference both to the Enryaku-ji's location atop Mount Hiei, and also after the era during which it was erected, like Enryaku-ji. Because it was one of the two Tokugawa bodaiji and because it was destroyed in the closing days of the war that put an end to the Tokugawa shogunate, it is inextricably linked to the Tokugawa shōguns.
Once a great complex, it used to occupy the entire heights north and east of Shinobazu Pond and the plains where Ueno Station now stands. It had immense wealth, power and prestige, and it once consisted of over 30 buildings. Of the 15 Tokugawa shōguns, six are buried here.
Many temple structures were destroyed in the great Meireki fire of 1657. A new hall was constructed inside the enclosure of Kan'ei-ji in 1698. The temple and its numerous annexes were almost completely destroyed during the Boshin War's Battle of Ueno and never restored.