If you drive down route 169 from Nara toward the city of Sakurai you will see a huge black “o-tori” that stands at the entrance of a parking area for Miwa shrine (Miwa-jinja or Miwa-myojin in Japanese).
This is the largest o-tori in Japan and the jinja is located at the base of a mountain. There is an ancient cedar tree there that a white snake (actually a reincarnation of the myojin) is reincarnated in. But you might not find many references to it on the web because the animistic details of the shrine might not have been written about much in English. And the history of this shrine, one of the oldest, is sometimes debated because of the different branches of shinto (and varying beliefs) that have appeared since then.
Raising a family in Thailand // Documenting Issan food, culture, music, and people
I have been to Miwa ginja several times in the past and most recently 5 years ago with Kimiko Obasan. It is a very special place along the yamanobenomichi. Unfortunately I have yet to see the white snake.