Background
He was the son of Hugh McManus (1747–1826) and Mary McManus (1751–1834).
United States representative lawyer politician
He was the son of Hugh McManus (1747–1826) and Mary McManus (1751–1834).
He attended Lansingburgh Academy. Then he studied law with John Bird, was admitted to the bar, and commenced practice in Troy, New New York
He was Surrogate of Rensselaer County from 1815 to 1818, and District Attorney from 1818 to 1821. McManus was elected as an Adams man to the 19th United States Congress, holding office from March 4, 1825, to March 3, 1827. Afterwards he resumed the practice of law.
In 1832, McManus ventured into land speculation, and was one of the founders of the Galveston Bay and Texas Land Company.