John McDonald (May 24, 1837 – January 30, 1917) was an American soldier and politician. Born in Dingle, County Kerry, Ireland, McDonald attended local schools. He immigrated to the United States and enlisted in the United States Army at Boston, Massachusetts, in 1857. He joined his regiment in Arizona, and served in the Cavalry Corps of the Army of the Potomac throughout the American Civil War. After the war, McDonald was ordered to the West, where he again took part in several campaigns against Native Americans. He retired as a captain of Cavalry on July 1, 1868 for disabilities incurred in the line of service.