Charles Augustus Rawson (May 29, 1867 – September 2, 1936) was an unelected United States Senator from Iowa for nine months in 1922.

Born in Des Moines, he attended the public schools and Grinnell College.

He engaged in banking and the insurance business and also in the manufacture of clay products, and was a member of the board of trustees of Grinnell.

On February 17, 1922, Rawson was appointed by Governor Nathan Kendall as a Republican to the U.S. Senate to fill the vacancy caused by the resignation of William Squire Kenyon.

From the outset, it was understood that he would serve for only a short time; in announcing the appointment, Governor Kendall stated that "It is understood that Mr. Rawson will not aspire to continue in the office but will serve only until a senator can regularly be chosen.