KATZENELSON, NISSAN (1862–1923), Russian Zionist. Born in Bobruisk, Belorussia, he completed his studies in physics in Berlin. He settled in Libau (Liepaja), where he worked in his father's timber business. Joining the Zionist movement at its inception, at the Third Congress (1899) he was elected a director of the *Jewish Colonial Trust. He was one of *Herzl's close aides and made the preparations for his Russian journey, on which he accompanied him (1903). Herzl appointed Katzenelson as his personal representative in all negotiations with the Russian authorities. In 1905 he was elected chairman of the board of the Jewish Colonial Trust. He participated in the activities of the League for Equal Rights for Jews in Russia. Elected to the First Duma (1906), Katzenelson joined the Russian liberal Kadet party, and as its spokesman took part in the work of the Duma finance committee. When the First Duma was dissolved, he was among the signatories of the manifesto calling for civil disobedience and the non-payment of taxes ("The Vyborg Manifesto"), for which he was sentenced to six months' imprisonment. After his release, he concentrated on local communal work and was chairman of the committee for Jewish emigration in Libau, one of the chief Baltic ports of Jewish emigration from Russia. In World War I he moved to Petrograd and helped in relief work for Jewish refugees, returning to Libau in 1918.
S.L. Zitron, Leksikon Ẓiyyoni (1924), 594–5; Yevreyskaya Letopis, 3 (1924), 230–1; J. Slutzky, in: Bobruisk, 2 (Heb. and Yid., 1967), 518–9 and index.