Martin Augustine Knapp (November 6, 1843 – February 10, 1923) was a United States federal judge.
Born in Spafford, New York, Knapp received a B.A. from Wesleyan University in 1868 and read law to enter the Bar in 1869. He entered private practice in Syracuse, New York in 1870, and was counsel for the municipal corporation of Syracuse 1877 to 1883. He was a member of the Interstate Commerce Commission from 1897 to 1910, serving as its Chairman from 1898 to 1910.
On December 12, 1910, Knapp was nominated by President William H. Taft to a new joint seat on the United States Commerce Court and the United States Court of Appeals for the Second Circuit, created by 36 Stat. 539. He was confirmed by the United States Senate on December 20, 1910, and received his commission the same day. His service on the Commerce Court was terminated on December 13, 1913, due to abolition of the court, and on January 1, 1916, he was reassigned to the United States Court of Appeals for the Fourth Circuit. He served thereafter until his death, in Washington, D.C.
He served as mediator in several disputes between the public and the railroads. He was a member of several economic societies.[1]