Horatio Collins King (December 22, 1837 – November 15, 1918) was a Union Army soldier who received the Medal of Honor for his actions during the American Civil War. He also served as a U.S. lawyer, politician and author and was admitted to the bar in New York City in 1861. He served in the armies of the Potomac and Shenandoah during the Civil War from August 1862 until May 1865, when he resigned with the rank of brevet colonel. King earned the Medal of Honor for service near Dinwiddie Courthouse, Virginia, on March 31, 1865. King was the son of the Postmaster General of the United States under President James Buchanan.