KOCK (Kotsk), town in the province of Lublin, E. Poland. Jews first settled in Kock at the beginning of the 17th century; an organized community existed from the middle of the century. One of the sons of Moses b. Isaac Judah *Lima (author of Ḥelkat Meḥokek) served as rabbi in Kock from 1670. In 1699 the Jews were granted unrestricted rights to settle by the owner of the town. According to the census of 1765, there were 793 Jews in the community and the surrounding villages, 489 of them in the town itself. Of the 108 Jewish families of Kock, 62 owned the houses that they occupied. By 1827 the number of Jews in the town had risen to 645 (36% of the total population), by 1857 to 1,480 (56%), and by 1897 to 3,014 (64%). About half of the Jews earned their livelihood from tailoring, hat-making, and shoemaking. Others were tanners, carpenters, potmakers, and locksmiths. In 1809 Berek *Joselewicz fell in a battle which was fought on the outskirts of the town. He was buried there.
When the "court" of the ẓaddik Menahem Mendel of *Kotsk was established in 1829, Kock became an important center of *Ḥasidism. In 1913 a yeshivah was founded in the town. The Jewish workers of Kock began to organize themselves into labor unions from 1905. Zionist organizations, particularly the *General Zionists and *Po'alei Zion, were active in Kock, as were the *Bund and *Agudat Israel. In 1926 nine of the 12 members of the municipal council were Jews. According to the 1921 census, the Jewish population of the town numbered 2,092 (54%); in 1927 there were 2,529 (68%). The last rabbi of Kock (from 1924) was R. Joseph Morgenstern, a ẓaddik from 1929; he perished in the Holocaust. The Ḥasidim of Kock are described by J. *Opatoshu in his book In Polish Woods (1938). About 3,000 Jews were in Kock after the German occupation in September 1939 and the arrival of refugees. In August 1942 around 100 Jewish families were deported to Parczew en route to Treblinka. Others were sent to Treblinka via Lukow. No Jews returned to the town after World War II.
R. Mahler, Yidn in Amolikn Poyln in Likht fun Tsifern (1958), index; B. Wasiutyński, Ludność żydowska w Polsce… (1930), 35; M. Balaban, in: Studja historyczne (1927); Sefer Kock (Heb. and Yid., 1961).