Calicioid lichens and fungi form a diverse polyphyletic group whose species richness is often associated with old-growth forests and ecological continuity. One of the last intact forest landscapes south of the 50th parallel in Québec includes the Ya'nienhonhndeh territory, which has been the focus of a protected area project directed by the Huron-Wendat First Nation for more than ten years. To contribute to the characterization of its conservation value, we report the calicioids from the area. We identified 34 species in eight genera from 187 samples collected in old-growth stands of balsam fir, black spruce and yellow birch. Our four most remarkable discoveries are Chaenotheca nitidula Tibell (n = 11), Chaenothecopsis australis Tibell (n = 1), and C. tsugae Rikkinen (n = 2), which are reported for the first time from the province, as well as Sclerophora coniophaea (Norman) Mattsson & Middelb. (n = 18), which is rare in North America and was previously reported only once in Québec. As a result of this inventory, the Ya'nienhonhndeh is now the second richest area known for calicioids in Québec, after Parc national de la Gaspésie. We conclude that it is an ancient forest ecosystem whose conservation value is high based on its unique biodiversity, and that it warrants protection.