Kingdom of Galicia–Volhynia
Eastern Galicia was the heartland of the medieval Kingdom of Galicia–Volhynia, currently spread over the provinces of Lviv, Ivano-Frankivsk, and Ternopil in modern western Ukraine. Along with Poles and Ukrainians, Jews were one of the three largest ethnic groups in Eastern Galicia with almost 900,000 people by 1910. From the late 18th century until the early 20th century eastern Galicia had the largest concentration of Jews of any region in Europe.