In the middle of the 8th century the Buddhist priest Shōdō Shōnin (735–817) established a hermitage at Nikkō. For centuries the mountains served as a training ground for Buddhist monks, though the area fell gradually into obscurity. Nikkō's enduring fame was sealed, however, when it was chosen as the site for the mausoleum of Tokugawa Ieyasu, the warlord who established the shogunate that ruled Japan for more than 250 years.

Ieyasu was laid to rest among Nikkō's towering cedars at a much less grand Tōshō-gū in 1617. Seventeen years later his grandson, Tokugawa Iemitsu, commenced work on the colossal shrine that can be seen today, using an army of some 15,000 artisans from across Japan who took two years to complete the project.