Beydagh or Baydag is a village in the Zangezur uezd of the former Yelizavetpol (Ganja) governorate, later in the former Gafan district, and currently in the Syunik province. It lies at a 5 km distance from Gafan, on the left bank of the Okhchu River.

The village was inhabited by 13 Azerbaijanis in 1831, 51 in 1873, 68 in 1886, 118 in 1897, 193 in 1904 and 58 Azerbaijanis in 1914. In 1918 the inhabitants of the village were massacred or driven out having been exposed to Armenian aggression. The Azerbaijanis, who left the village, managed to return to their own homes in 1923–1924 following the establishment of Soviet power in the present-day Armenian territory. The village was inhabited by 28 Azerbaijanis in 1926, 32 in 1931 and 37 Azerbaijanis in 1939. Armenians were removed to the village in 1929- 1930. Later the former inhabitants of the village were registered in the census as the inhabitants of the town of Gafan.

The toponym was coined by combining the word “bey (bak)” used in Azerbaijani in the sense of “tall, great” and the word “dagh” (a mountain) and denotes “a village by the high, great mountain”. It should also be added that “the word “bey” was used in Old Turkic as “bek” in the sense of “a hill”. In the initial position of the toponyms, the word “bey” means “tall, great”, “a hill”, whereas in the final position “agha” denotes “a rich man”.

In 1959 the village was integrated into the town of Gafan.

Geographic coordinates: latitude: 39°12’ N., longitude: 46°24′ E.