Charles William Harkness (December 17, 1860 – May 1, 1916)[1] was an American businessman and railroad executive.

He was a son of Stephen V. Harkness, an original investor in the company that became Standard Oil, and his second wife, the former Anna M.

"[3] On his father's death in 1888, Charles inherited stock in Standard Oil amounting to the second largest holding in the company, surpassed only by that of the Rockefeller family.

[4] Harkness became a director at Standard Oil and was a director of the Southern Pacific Railway Company; the Chicago, Milwaukee and St. Paul Railway; the Baltimore and Ohio Railroad; and the Tilden Iron Mining Company.

Harkness purchased the Henry Flagler townhouse at 685 Fifth Avenue in New York City and also owned a home in Madison, New Jersey that was designed by James Gamble Rogers and a winter home in St. Augustine, Florida.

[6] Since he had no children, the large portion of his Standard Oil stock was left to his brother Edward S.