In 2017 excavations were started on the fortification in Porębek, Kętrzyn district, site 3. Two excavations were performed during the work along the NE-SW axis (Figure 3). Trench 1/2017 (measuring 10 x 5 m) was opened within the “upper castle” – it included the area from the top of the rampart located on the NW side of this area and part of the courtyard. Trench 2/2017 (measuring 10 x 3 m) was delineated within the “lower castle” – it encompassed the courtyard from its SE edge and was perpendicular to the ditch. A total area of 80 square meters was uncovered. The interesting remains of a 13th-century building of the two-part stronghold were discovered. The source materials suggest that this place was inhabited earlier – in the Early Iron Age and in the Early Middle Ages. The stratigraphy seems to indicate large scale construction work, during which time the terrain was completely transformed. The discovery at the foot of the upper castle, in the Guber river valley, was extremely valuable.