Charles Herschel Sisam (8 September 1879, Cedar Rapids, Iowa – 4 December 1964) was an American mathematician.
[3] While working on his Ph.D., Sisam was a mathematics instructor at the United States Naval Academy from 1904 to 1906.
[4] He was an instructor in 1906–1907, a research associate in 1907–1909, and an assistant professor in 1909–1918 at the University of Illinois.
He did research on algebraic surfaces and was an Invited Speaker at the ICM in 1928 in Bologna.
[5] He was on the editorial staff of the Transactions of the American Mathematical Society from 1930 to 1936.