The northern wall is the longest - 93.5 m. The embankment height at the northern wall of the Castle is up to 6.5 m At a distance of 7.5 m from the northern wall of the castle by order of Vytautas the Lithuanian Grand Duke, it was dug a moat 18-19 m wide, which connected the two rivers Lideya and Kamenka, separated the fortification from the city itself.