Cassius Clay Dowell (February 29, 1864 – February 4, 1940) was a Republican U.S. Representative from Iowa. He served from 1915 to 1935, and again from 1937 until his death in 1940, with the interregnum caused by an unsuccessful campaign for reelection in 1934.
Born on a farm near the unincorporated town of Summerset, Iowa (in Warren County, near Indianola) Dowell attended the public schools, Baptist College in Des Moines, Iowa, and Simpson College in Indianola, Iowa. In 1886 he graduated from the liberal arts department of Drake University in Des Moines, Iowa, and graduated from Drake University Law School the following year. He was admitted to the bar in 1888 and commenced practice in Des Moines.
From 1894 to 1898, Dowell served as member of the Iowa State House of Representatives. He served in the Iowa State Senate from 1902 to 1912.
In 1914, Dowell was elected as a Republican to represent Iowa's 7th congressional district. He was re-elected to this seat eight times, until reapportionment between 1930 and 1932 moved his home county into Iowa's 6th congressional district, prompting him to run for the seat in that district. He won the 1932 race by more than 13,000 votes], surviving the Roosevelt landslide. Yet he was surprised two years later, when former Iowa Supreme Court Justice Hubert Utterback upset him by over 4,000 votes. He had served nearly twenty years, in the Sixty-fourth and the nine succeeding Congresses (March 4, 1915-January 3, 1935). He had served as chairman of the Committee on Elections (in the Sixty-sixth and Sixty-seventh Congresses), and on the Committee on Roads (in the Sixty-eighth through Seventy-first Congresses).