Martin Ingham Townsend (February 6, 1810 Hancock, Massachusetts – March 8, 1903 Troy, New York) was an American lawyer and politician from New York.
He moved with his parents to Williamstown, Massachusetts in 1816. He attended the common schools, and graduated from Williams College in 1833. Then he studied law, was admitted to the bar in 1836, and commenced practice in Troy, NY. He was District Attorney of Rensselaer County from 1842 to 1845. He was a delegate to the New York State Constitutional Convention of 1867. In 1869, he ran on the Republican ticket for New York State Attorney General, but was defeated by the incumbent Democrat Marshall B. Champlain. He was a Regent of the University of the State of New York from 1873 to 1903.
Townsend was elected as a Republican to the 44th and 45th United States Congresses, and served from March 4, 1875 to March 3, 1879. He was United States Attorney for the Northern District of New York from 1879 to 1887. He retired from legal practice in 1901.
He was buried at the Oakwood Cemetery in Troy.