(Aug. 10, 1861), in the American Civil War, successful Southern engagement fought between 5,400 Union troops under General Nathaniel Lyon and a combined force of more than 10,000 Confederate troops and Missouri Militia commanded by General Benjamin McCulloch and General Sterling Price, 10 miles (16 km) southwest of Springfield, Mo. Union General Franz Sigel attacked the rear of the Confederate forces with 1,200 men while Lyon led a frontal attack with the main Union force. Sigel was repulsed, and after several hours of fighting Lyon was killed. With casualties heavy on both sides, the Union forces retreated toward Springfield.