NASIELSK (Rus. Nasyelsk), town in Warszawa province, E. central Poland. It received its first municipal privileges in 1386. The date of the first Jewish settlement is unknown, but a wooden synagogue was erected in 1650. The community listed 1,410 Jews in 1808, 4,741 in 1910 (76% of the total population), and 2,691 in 1921. Jews were not integrated into the economic life of the town and many of them emigrated after World War I. During the period of Polish independence, there was a significant number of unemployed and poor among the Jews, a situation which deteriorated even further as a result of a boycott by Polish antisemites. Tension between Jews and Christians came to the fore in 1923, when the latter accused the Jews of a ritual murder. Dominant in the community was the *Agudat Israel, which in 1920, 1924, and 1931 won half of the seats of the community council. Among the educational institutions, there were the Beth Jacob schools of the Agudat Israel, the *Tarbut of the Zionists, and a Yiddish school, as well as such cultural institutions as a library and various drama circles. The wooden synagogue was rebuilt in 1880. Renowned ẓaddikim, such as R. Jacob Landa (d. 1886) and Ezekiel ha-Levi b. Meir Jehiel (d. during the Holocaust) settled in the town.
Sefer ha-Ẓeva'ot, 1 (1945), 145.