Jacob Gartner Lauman was an American businessman from Iowa and a controversial general in the Union Army during the American Civil War.

The Jackson expedition, preceding and related to the siege of Jackson immediately followed the Confederate surrender of Vicksburg, Mississippi on July 4, 1863 to Union Army Major General Ulysses S. Grant commanding the Union Army of the Tennessee. The Confederate Army of Mississippi at Vicksburg, under the command of Lieutenant General John C. Pemberton, had been isolated in the Vicksburg defenses by Grant's forces since May 18, 1863. The Confederates were under constant artillery bombardment, had to fight off a series of Union Army attacks and could not receive supplies of food and ammunition during the siege.