The town has a long history and the name Mudurnu comes from the Byzantine princess Modrene (Μωδρηνή in Byzantine Greek), and the ruins of the Byzantine castle can still be seen above the town.
In 1920, during the Nationalists' push to gain control over the country, İbrahim Çolak with the Kuva-yi Milliye besieged forces loyal to the Porte for three days, May 13 to 15, before taking the town.