Knin Fortress (Croatian: Kninska tvrđava) is a partially ruined fortress located just above Knin, Croatia. It is one of the biggest and most significant defensive strongholds, and a historical town in the Šibenik-Knin County in the Dalmatian hinterland. The construction of the fortress started as early as 9th century, while the current state was brought up in 17th and 18th centuries.