The Caglayan Valley is located in Findikli district of Rize province, and represents a 34.7-km linear stretch that starts in Findikli district and ends in the Yusufeli district borderland of Artvin province in Turkey. Moreover, the valley is the home of two endemic viper species, Pelias barani (a Turkish endemic) and Pelias kaznakovi (a Caucasus endemic), that are classified by the IUCN as Near Threatened and Endangered, respectively. Here, Pelias barani is documented in the Caglayan Valley for the first time. Due to several threats, most notably a proposed hydroelectric power plant (HPP), these viper species will face increasing challenges such as habitat loss and fragmentation in the near future. Therefore, this study emphasizes that the Caglayan Valley should be a protected area in terms of these two viper species, and it also shows this area to be the nearest contact zone between P. barani and P. kaznakovi found thus far.