The River Teeth Literary Nonfiction Book Prize is an annual competition administered by the journal River Teeth: A Journal of Nonfiction Narrative, a publication long anchored in the essayistic and narrative traditions of the form. The prize is for a book-length manuscript of literary nonfiction, and all submissions are screened by the journal's co-editors before a final selection is made by the guest judge, the author Ander Monson. The winning manuscript receives $1,000 and publication by The University of New Mexico Press, an academic press with a substantive list in creative nonfiction and the literature of the American West. The contest operates with a clear editorial hierarchy: the co-editors serve as the initial curatorial filter, and the guest judge holds final discretion. This structure signals that the prize is not a general open call but a focused search for manuscripts that align with River Teeth's established sensibility—narrative-driven, formally considered, and grounded in the real. The journal has historically encouraged submissions from underrepresented voices, explicitly including BIPOC, LGBTQ+, and disabled writers, and that invitation is stated in the guidelines rather than implied. For the entrant, the material terms are straightforward: a $27 submission fee, a deadline of November 1, 2026, and, for U.S. entrants who provide a mailing address, a one-year subscription to River Teeth beginning in the spring. The prize does not include an advance beyond the stated $1,000, and publication is with a university press rather than a commercial house. The value of the prize lies in its combination of a reputable press, a journal with a defined editorial identity, and a judge whose own work in nonfiction and hybrid forms is well known. The guidelines are specific: include a cover letter with contact information and a brief bio, but do not include a summary of the manuscript. That instruction is not incidental—it reflects the journal's preference for the work to speak first.