Okunikko (������, Okunikkō, "Inner Nikko") is the mountainous region of Nikko that lies at a higher elevation, deeper into the mountains west of Nikko's city center. Part of Nikko National Park, Okunikko offers beautiful natural scenery, including waterfalls, lakes, marshlands, streams and hot springs.

Okunikko has long been a popular destination for escaping the heat of summer. Beautiful hiking trails attract outdoor lovers from spring to autumn, while winter scenery can be enjoyed during the rest of the year. The regions also offers some of the most spectacular autumn colors near Tokyo during the month of October.