William Telemachus McManus (28 November 1780-18 January 1835) was a member of the US House of Representatives (NR-NY 9) from 4 March 1825 to 3 March 1827, succeeding James L. Hogeboom and preceding John Dean Dickinson. Born in Brunswick, he practiced law in Troy before serving as Rensselaer County surrogate from 1815 to 1818, district attorney from 1818 to 1821, and in Congress.