John Alexander Logan (February 9, 1826 – December 26, 1886) was an American soldier and political leader.
He served in the Mexican-American War and was a general in the Union Army in the American Civil War.
He served the state of Illinois as a State Senator, a Congressman, and a U.S. Senator and was an unsuccessful candidate for Vice President of the United States with James G. Blaine in the election of 1884.
As the 3rd Commander-in-Chief of the Grand Army of the Republic, he is regarded as the most important figure in the movement to recognize Memorial Day (originally known as Decoration Day) as an official holiday.