Busk was granted town charter in 1411 by Siemowit IV, Duke of Masovia. In the Polish-Lithuanian Commonwealth, it belonged to the Belz Voivodeship, and was the seat of a separate administrative unit, the Land of Busk. The town remained part of Poland until the first partition of Poland (1772), when it was seized by the Habsburg Empire, and remained in Austrian Galicia until late 1918. In the interwar period, Busk belonged to Tarnopol Voivodeship of the Second Polish Republic, until Soviet invasion of Poland (September 1939).
In 1913, the population of Busk was 8,000, including 3,500 Poles, 2,700 Jews and 1,800 Ukrainians.
Busk had a very active Jewish community before World War II. The first synagogue was built in 1502. The old Jewish cemetery was renowned by its ancient tombstones . On July 1, 1941, German forces occupied Busk. The Jewish population was transferred to a ghetto then murdered on May 21, 1943. 1500 Jews perished during this operation.
Kalush (Ukrainian: Kalush; Polish: Kałusz) is a city set in the foothills of the Carpathian Mountains, in the Ivano-Frankivsk province of western Ukraine.The earliest known mention of Kalush is the accounting of a village of that name in a chronicle dated 1437. In 1547 Kalush received city rights. It was known for producing malt, its brewery and salt mining, later it became also known as a city of chemical industry specializing in producing nitrate. In 1772, following the Partitions of Poland, the town was seized by the Habsburg Empire, where it remained until 1918.
Since the 16th century, a Jewish community had flourished in the city and at times constituted a majority of its population. In the middle of the 19th century, the Mayor of Kalush was a Jew (Moyshe Meyer).
In the Second Polish Republic, Kalush/Kalusz was the seat of a county in Stanislawow Voivodeship. Its population was 15,000, almost equal proportions of Poles, Ukrainians and Jews. Following the 1939 Invasion of Poland, the town was annexed by the Soviet Union. After the German occupation the Jews were driven into the ghetto: a total of 7,000 – including Jews from Kalush suburbs. At the end of 1942 the ghetto was liquidated and its inhabitants were send to the death camp in Belzec.