The present paper contains information on a new beaver colony discovered in the Chornyi mochar tract, which is located in the lowland part of Transcarpathia (= Zakarpattia Region). This rodent species disappeared from the territory of Transcarpathia most likely in the 18th century. Its first reappearance was recorded in 2003. Since, the Eurasian beaver has demonstrated a rapid expansion, primarily along the main rivers. The discovered by us colony allows to suggest that the beaver is continuing its dispersal, entering far into the main river’s tributaries and other shallower water bodies. Consequently, we are witnessing not only the expansion of the species’ geographical range, but also the enlargement of the number of habitat types occupied by the animal. The possibilities and supposed consequences of the species’ further expansion within the tract are shown as well.