Izborsk (Russian: Избо́рск; Estonian: Irboska; Seto: Irbosk, Irbuska) is a rural locality (village) in Pechorsky District of Pskov Oblast, Russia.

Although his burial mound is still shown to occasional tourists, archaeological excavations of long barrows abounding in the vicinity did not reveal the presence of the Varangian settlement at the site, which indicates that Izborsk was an important centre of the early Krivichs.

The next mention of the town in Slavonic chronicles dates back to 1233, when the place was captured by the Livonian Brothers of the Sword.

In the later 16th century, Izborsk was one of the smaller but strategically-important fortresses that protected the northwestern Russian borders from invasion.

The fortress was supposed to be impregnable and so the seizure of it in 1569 by a small Lithuanian regiment came as such a shock to Ivan the Terrible.

The relative ease and the suspicious circumstances of the seizure of the fortress deeply troubled the already-paranoid Ivan.

In the dead of night, Teterin, a Russian turncoat disguised as an oprichnik, ordered the gates of the town be opened in the name of the oprichnina, which allowed the enemy regiment to enter and overtake the fortress (the town of Izborsk, however, was never listed as territory in which oprichnina governance applied).

With rumours of disaffection and growing discontent throughout the country on the rise, Ivan feared that other cities would soon follow the treasonous example of Izborsk.

[2] During the Siege of Pskov (1581), Izborsk was captured by the Lithuanian troops, but after the Truce of Yam-Zapolsky (1582) handed over to the Tsardom of Russia.

The fortress' southeast side was equipped an underground stone hallway that provided access to a spring well.