Clarence Dickinson Long (December 11, 1908 - September 18, 1994), a Democrat, was a U.S. Congressman who represented the 2nd congressional district of Maryland from January 3, 1963 to January 3, 1985. He received his bachelor's degree from Washington and Jefferson College in 1932, and his master's degree and Ph.D. from Princeton University in 1935 and 1938, respectively. He also served in the United States Navy during World War II.
Preceded by: Daniel B. Brewster U.S. Congressman, Maryland's 2nd District 1963 - 1985 Succeeded by: Helen Delich Bentley