The American Civil War was fought between the rebelling Confederate States (South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, Texas, Virginia, Arkansas, Tennessee, and North Carolina), and the loyal states of the United States of America (California, Connecticut, Delaware*, Illinois, Indiana, Iowa, Kansas, Kentucky*, Maine, Maryland*, Massachusetts, Michigan, Minnesota, Missouri*, Nevada, New Hampshire, New Jersey, New York, Ohio, Oregon, Pennsylvania, Rhode Island, Vermont, West Virginia*, and Wisconsin). Answering the question "Who was in the Civil War?" is not an easy one to answer. Many individuals participated in the American Civil War, as many as 3,164,000 men (and women) played military roles during this wartime period, and the nation (U.S.A./C.S.A. combined) had a population of 31,443,321 as a whole in 1860. Below is a listing of the most prominent individuals to participate in this struggle. The Union (United States of America) [Lincoln, Johnson, McClellan, Grant, Meade] Civilian Leadership Abraham Lincoln - 16th President of the United States Montgomery Blair - U.S. Postmaster General Gustavus V. Fox - Assistant Secretary of the Navy Hannibal Hamlin - 1st Term Vice President of Abraham Lincoln Andrew Johnson - 2nd Term Vice President of Abraham Lincoln, Future U.S. President William H. Seward - Secretary of State Edwin M. Stanton - Secretary of War Thaddeus Stevens - Member of the U.S. House of Representatives from Pennsylvania Benjamin Wade - United States Senator from Ohio Gideon Welles - Secretary of the Navy Military Leadership George B. McClellan - Major General Ulysses S. Grant - Lieutenant General, and Future U.S. President Robert Anderson - Major, commander of Fort Sumter, promoted to Brigadier General Don Carlos Buell - Major General Benjamin Butler - Major General Ambrose Burnside - Major General John A. B. Dahlgren - Rear Admiral Samuel Francis Du Pont - Rear Admiral David Farragut - Admiral Andrew Hull Foote - Rear Admiral John C. Frémont - Major General Henry Halleck - Major General Herman Haupt - Brigadier General, railroad engineer Joseph Hooker - Major General Henry Jackson Hunt - Chief of Artillery in the Army of the Potomac, Brevet Major General Samuel Phillips Lee - Rear Admiral Irvin McDowell - Major General George Meade - Major General Montgomery C. Meigs - Brigadier General, Brevet Major General John Pope - Major General David Dixon Porter - Admiral William Rosecrans - Major General Winfield Scott - Brevet Lieutenant General Philip Sheridan - Major General William Tecumseh Sherman - Major General George Henry Thomas - Major General John L. Worden - Lieutenant in command of the U.S.S. Monitor at Hampton Roads Other Notable Persons John Brown - Abolitionist, unsuccessfully raided Harper's Ferry in 1859 Samuel Colt - developed the first viable mass-produced revolvers prior to the Civil War Frederick Douglass - former slave, orator, writer, and leader of the abolitionist movement John Ericsson - inventor and engineer, designed the USS Monitor William Lloyd Garrison - Abolitionist, editor of the newspaper, The Liberator Horace Greeley - publisher and editor of the New York Tribune, opponent to slavery Benjamin Tyler Henry - gunsmith and manufacturer, inventor of the Henry Rifle William Mason - significant supplier of locomotives and rifles for the Union Army Samuel Morse - co-inventor of the single line telegraph system and Morse Code Robert Parker Parrott - soldier & inventor of military ordnance at West Point Foundry Allan Pinkerton - head of the Union Intelligence Service, detective and spy The Confederacy (Confederate States of America) [Davis, Lee, Jackson, Longstreet, Beauregard] Civilian Leadership Jefferson Davis - 1st and only President of the Confederate States of America Alexander Stephens - Vice President of the C.S.A. Judah P. Benjamin - 1st Attorney General, 2nd Secretary of War, 3rd Secretary of State Thomas Bragg - 2nd Attorney General John C. Breckinridge - 5th Secretary of War George Davis - 4th Attorney General Robert Hunter - 2nd Secretary of State Stephen Mallory - Secretary of the Navy Christopher Memminger - Secretary of the Treasury Francis W. Pickens - Secessionist Governor of South Carolina George Randolph - 3rd Secretary of War John Reagan - Postmaster General James Seddon - 4th Secretary of War Robert Tombs - 1st Secretary of State LeRoy Pope Walker - 1st Secretary of War Thomas Hill Watts 3rd Attorney General Military Leadership Robert E. Lee - General commanding the Army of Northern Virginia, General-in-Chief of all Confederate Forces Edward Porter Alexander - General, Longstreet's Chief of Artillery Joseph Reid Anderson - Brigadier General, owner of Tredegar Iron Works Richard H. Anderson - Lieutenant General P. G. T. Beauregard - General, commanded firing on Fort Sumter Braxton Bragg - Lieutenant General Franklin Buchanan - Captain of the C.S.S. Virginia, Admiral on board the C.S.S. Tennessee Patrick R. Cleburne - Major General Samuel Cooper - Full General, highest ranking Confederate general during the war Jubal Early - Lieutenant General Richard S. Ewell - Lieutenant General, senior commander under Jackson and Lee Nathan Bedford Forrest - Cavalry General Josiah Gorgas - Chief of Ordnance for the Confederate Army Wade Hampton III - Lieutenant General Ambrose Powell Hill - Lieutenant General John Bell Hood - Lieutenant General Thomas J. "Stonewall" Jackson - Lieutenant General Albert Sidney Johnston - General, killed at Shiloh Joseph E. Johnston - Full General James Longstreet - Lieutenant General John Hunt Morgan - Brigadier General John S. Mosby - Colonel, guerrilla leader Sterling Price - Major General William Quantrill - leader of Quantrill's Raiders Raphael Semmes - Admiral, Captain of CSS Alabama Edmund Kirby Smith - General James Ewell Brown "Jeb" Stuart - Major General, cavalry Richard Taylor - Lieutenant General Stand Watie - Brigadier General Joseph Wheeler - Major General Other Notable Persons John Wilkes Booth - famous stage actor who assassinated Abraham Lincoln at Ford's Theatre Jedediah Hotchkiss - famous cartographer and topographer Jean Alexandre LeMat - New Orleans physician and inventor of the LeMat Revolver Samuel A. Mudd - physician, assisted John Wilkes Booth Sir Joseph Whitworth - English engineer and inventor, designed the Whitworth Rifle Women of the Civil War Please see: Women of the Civil War * Border states with slavery in 1861: In Kentucky and Missouri, pro-secession "governments" declared for the South but never had significant control of the states. Also, West Virginia separated from Virginia and became part of the Union during the war, on June 20, 1863. Nevada also joined the Union during the war, becoming a state on October 31, 1864.