This chapter explores how an ecoerotic study of nature mysticism can be utilized to enhance our understanding of the relationship between eroticism, ecology, and nature mysticism. In particular, I introduce what I call an “ecoerotic ontology” to explain the ethical significance of Henry David Thoreau’s mystical vision of nature. By placing queer theory in dialogue with nature mysticism, I argue that Thoreau’s mystical vision of nature suggests that cultivating erotic contact with the earth—embracing the wild—can evoke a profound sense of wonder that is both morally transformative and a rich source of ecological knowledge. Ultimately, I suggest that Thoreau’s concern for social justice and the wellbeing of nature spring from the same mystical roots, and these roots are erotic to their core.