[3] Khoy was named in ancient times for the salt mines that made it an important spur of the Silk Route.

[5] Around 37 BC, Marc Anthony had crossed the plain that is located between Khoy and Marand during one of the many and frequent Roman–Parthian Wars.

The return of Khoy to the central government of Iran was during the beginning of Qajar period during Agha Mohammad Khan's reign.

Khoy was attacked in 1827 by the Russian Empire who was attempting to seize the last of the Caucasian territories of Iran comprising Armenia and what is now Azerbaijan during the Russo-Persian War (1826–1828).

Until 1828, Khoy had a large number of Armenians, however, the Treaty of Turkmenchay following the outcome of the 1826–1828 war and the victory over the neighbouring Ottoman Empire as concluded in the Treaty of Adrianople, encouraged the mass resettlement of Armenians from both Turkey and Iran in the Russian-controlled territory of modern Armenia.

[6] He noted further that in the immediate villages around Khoy city there were a few more Armenians, but the vast majority had migrated to the north of the Aras river following Russia's victory over Persia in 1828 and the encouraged settling in the newly incorporated Russian regions of Eastern Armenia.

[2] Khoy County's population history and administrative structure over three consecutive censuses are shown in the following table.