The Army of the Border was a Union army during the American Civil War. It was created from units in the Department of Kansas to oppose Sterling Price's Raid in 1864. Samuel R. Curtis was in command of the army throughout its duration.
Major General James G. Blunt, who commanded the District of South Kansas, was placed in command of the army's 1st Division, which was broken up into three brigade of volunteer cavalry regiments and a fourth of Kansas state militia units. Major General George Dietzler commanded the rest of the Kansas state militia units and organized them into the 2nd Division of the army.
Blunt's division fought at the battles of Lexington and Little Blue River before falling back and joining Curtis and the rest of the army at Westport. At the Battle of Westport, Curtis's two divisions were joined by Alfred Pleasonton's cavalry division from the Department of the Missouri, bringing the Union army to about 22,000, including Pleasonton's cavalry. After the battle, the militia units returned to their respective counties while Blunt's volunteers continued the pursuit along with Pleasonton's division. Blunt's division fought Price in the last major battle of the campaign at Newtonia.