Joseph Clay Blackburn (October 1, 1838 - September 12, 1918) was a Democratic Representative and Senator from Kentucky.
He was born near Spring Station, Kentucky. He attended Sayres Institute in Frankfort and graduated from Centre College in Danville in 1857. He studied law in Lexington and was admitted to the bar in 1858. He practiced in Chicago until 1860 when he returned to Woodford County, Kentucky and entered the Confederate Army as a private in 1861.
By the end of the Civil War and was promoted to the rank of lieutenant colonel. He settled in Arkansas in 1865, where he was engaged as lawyer and planter in Desha County until 1868 when he returned to Kentucky and opened law offices in Versailles.
He was a member of the State house of representatives from 1871 to 1875. He was then elected as a Democrat to the Forty-fourth and to the four succeeding Congresses (March 4, 1875 - March 3, 1885). He was the chairman of the Committee on the District of Columbia (Forty-fifth Congress) and the Committee on Expenditures in the Department of War (Forty-fifth and Forty-sixth Congresses).
He was elected to the United States Senate in 1885, was reelected in 1890, and served from March 4, 1885, to March 3, 1897. He failed to be reelected in 1896. He was the chairman of the Committee on Rules (Fifty-third Congress).
He was once again elected to the United States Senate in 1900 and served from March 4, 1901 to March 3, 1907, but failed in his next election bid in 1906.
He was appointed Governor of the Panama Canal Zone by President Theodore Roosevelt on April 1, 1907. He resigned in November 1909 and returned to his estate in Woodford County.
He died in Washington, D.C. and was interred in the State Cemetery in Frankfort.
Preceded by: James B. Beck United States Representative from Kentucky's 7th District 1875-1885 Succeeded by: William Breckinridge Preceded by: John Stuart Williams United States Senator (Class 3) from Kentucky 1885-1897 Succeeded by: William J. Deboe Preceded by: William Lindsay United States Senator (Class 2) from Kentucky 1901-1907 Succeeded by: Thomas H. Paynter