ENLithuania is known as the land of hill-forts. It has about 1000 hill-forts located on the quite small territory of 65200 sg.km. Hillforts date back to different periods, starting with establishments arranged at the turn of the second and first millennia BC to those abandoned in the thirties of the 15th century. These were wooden castles on approximately half of them in the first half of the second millennium. The network of these castles and its role in defending the young state of Lithuania against foreign enemy have not been investigated yet. The present article studies defensive systems of wooden castles in Lithuania, formed during the 13 th-14th centuries, i.e. in the period of the early feudal state of Lithuania. [p. 200].