Ainu have been known to inhabit the present site of Kurilsk since the 2nd millennium BCE, with their settlement known as Shana, and under Russian rule as Syana (). Russian colonists first appeared on Iturup in the late 18th century, with the Japanese erecting a military post in 1800. Tensions between Russian and Japanese colonists in the area led to the Treaty of Shimoda, which saw the southern Kuril Islands officially placed under Japanese rule in 1855, remaining so until the end of World War II.