Jordan Carson Mark (July 6, 1913 – March 2, 1997) was a Canadian-American mathematician best known for his work on developing nuclear weapons for the United States at the Los Alamos National Laboratory.

Mark joined the Manhattan Project in 1945, and continued to work at Los Alamos under the leadership of Norris Bradbury after World War II ended.

On the hydrogen bomb project he was able to bring together experts like Edward Teller, Stanislaw Ulam and Marshall Holloway despite their personal differences.

In July and August 1958, and again the following year, Mark was a scientific adviser to the United States delegation at the Conference of Experts on Detection of Nuclear Explosions.

He served on the United States Air Force's Scientific Advisory Board, and its Foreign Weapons Evaluation Group.

[3] Mark taught mathematics at the University of Manitoba, from 1938 until World War II, when he joined the Montreal Laboratory of the National Research Council of Canada in 1943.

A crash program to develop the hydrogen bomb was approved by President Harry S. Truman in January 1950 at Edward Teller's urging before the laboratory had a workable design.

Hans Bethe recalled that "There was a lot of controversy in Los Alamos in those days, and Carson always was imperturbable and stood in the middle of it and had a balanced judgment.

[2] In July and August 1958, and again the following year, Mark was a scientific adviser to the United States delegation at the Conference of Experts on Detection of Nuclear Explosions.

He was survived by his wife Kathleen, daughters, Joan, Elizabeth Mark and Mary, and sons, Thomas, Graham and Christopher, his brother, James and sister Dorothy .