Sidra was a small town located in the Bialystok region of Poland. The region was quite rural with an ethnically mixed population. The area has been inhabited for centuries by members of different nations and religions: Belarusians, Lithuanians, Ukrainians, Russyns, Gypsies, Tatars and Jews. Religions consisted of Roman Catholics, Russian, Greek and Ukrainian Orthodox Christians, Muslims, Orthodox, Conservative, and Progressive/Reform Jews.
The earliest known Jewish community was 17th century. In 1921, the Jewish population consisted of 465 people. The wooden synagogue was built by the end of the 18th or early 19th century. The main hall, square in plan, was sunk three steps below the vestibule floor level. The roof was flat. The Jewish town of Sidra was destroyed by the Nazi during World War II.http://www.billfarran.com/sidra.htm (db)