The Battle of Marais des Cygnes took place on October 25, 1864, in Linn County, Kansas during Price's Missouri Raid in the American Civil War. It is also called the Battle of Osage, and the Battle of Trading Post. It proved to be the first of three interconnected actions on this same day, all involving elements of Major General Sterling Price's Confederate Army of Missouri and the Union's Provisional Cavalry Division commanded by Major General Alfred Pleasonton. During this battle, two brigades of Pleasonton's cavalry under Colonels John F. Philips and Frederick Benteen caught up with Price's rear guard at Trading Post, Kansas, as it covered the crossing of the Marais des Cygnes River by the Southern supply train. Though unable to prevent the crossing or inflict serious damage on Confederate forces, Pleasonton's troopers did manage to capture 100 prisoners and two cannon, forcing Price to continue his retreat. This led in turn to a second engagement at Mine Creek later that morning, followed by a final battle at Marmiton River in the afternoon. The three Union victories won on this day sealed the fate of Price's campaign.

• http://en.wikipedia.org/wiki/Battle of Marais des Cygnes