Xianyu Cave is a limestone cavern system embedded in the Ca'eryan cliff face in the eastern part of the park, notable for containing both Taoist and Buddhist shrines within its chambers — an unusual combination that reflects the historical practice of mixing traditions in remote pilgrimage sites where institutional boundaries were harder to enforce.
The cave's interior includes stalactite formations and an underground stream, and the combination of geological formation and religious installation gives it a character that neither element alone would produce. It is less visited than the bamboo walk and waterfall circuits and a worthwhile detour for anyone spending more than a day in the park.