Portal:Military of the United States/Selected anniversaries/May 13
- 1846 - Mexican–American War: The United States declares war on Mexico.
- 1861 - American Civil War: Queen Victoria of the United Kingdom issues a "proclamation of neutrality" which recognizes the breakaway states as having belligerent rights.
- 1864 - American Civil War: Battle of Resaca – the battle begins with Union General Sherman fighting toward Atlanta.
- 1865 - American Civil War: Battle of Palmito Ranch – In far south Texas, more than a month after Confederate General Lee's surrender, the last land battle of the Civil War ends with a Confederate victory.
- 1943 - World War II: German Afrika Korps and Italian troops in North Africa surrender to Allied forces.