For the first time it was mentioned in 1147 as Unenezh.
The Magdeburg Right was granted in 1618 by king Sigizmund III together with an emblem - the picture of St.Yuri on a horse killing a dragon with a spear. The armed rider symbolized the important role of Nizhyn in fortified systems of Kyiv Rus', Great Lithuanian principality and later of Poland.
Since 1649 Nizhyn was a regimental town.