The main battleground is located in the Arcadia valley, between Pilot Knob and Shepherd Mountain. The railroad terminated at a landing in the town of Pilot Knob away from the hexagonal walls of Fort Davidson.
Union Brigadier General Thomas Ewing, Jr., commander of the District of St. Louis and the brother-in-law of William T. Sherman, had arrived at the fort on an inspection trip when he found the railroad cut off in his rear. Despite being outnumbered ten-to-one, he decided to stay and fight. The fort was a strong defensive position: hexagonal walls nine feet high and ten feet thick, surrounded by a dry moat nine feet deep. Two long rifle pits ran out from the walls, and a reinforced board fence topped the earthworks. The walls of the fort proper were not nearly large enough for the entire 1,500-man union garrison to reside, and access to the fort was through a drawbridge on the southeastern corner of the structure. At the time of the battle, there was a clear field of fire in every direction from the fort.
On September 27, action began at Fort Davidson proper. Price and his officers decided to take the fort in one massive assault. Price sent forces to attack the fort from several directions. One brigade went over the top of Pilot Knob, engulfing a small Union force there. Another Southern brigade attacked over the summit of Shepherd's Mountain. A third brigade skirted Shepherd's Mountain to attack the northwestern sides of the fort, and the forth confederate brigade attacked through the valley between the two mountains. Following fighting in which the Union troops were driven back by superior numbers, the rebels took control of Shepherd's Mountain to the southwest of the fort. A two gun confederate battery was mounted on Shepherd's Mountain, and the fire from those guns caused the smaller of the two riffle pits to be abandoned.
Unfortunately for Price, the assaults were not made at the same time, allowing the heavy guns of Fort Davidson to be directed at each Confederate brigade in turn. Only one of the brigades actually reached the fort under the hail of cannon and musket fire. When the Confederates reached the outer walls of the fort, they found the earthworks too steep to climb. During the assault, as the Southern army drew close, the Union troops were supplied with hand grenades from the fort's magazines. Shortly after the wooden-finned impact grenades were tossed over the walls, the attack was broken.
The disorganized Confederates fell back to into cover and prepared to assault the fort again the next day.
Price set his troops to building scaling ladders for an assault the next morning. After a vote from a council of war, Ewing (who had recently belatedly received orders from St. Louis to abandon the fort) decided his position was untenable and planned an escape. The Union soldiers draped the drawbridge over the moat in canvas to muffle the sounds of their movement. As the survivors withdrew undetected to the northwest (directly between two rebel encampments), they left a slow-burning fuse to the powder magazine, which exploded in a mighty blast well after the troops were gone. Despite the huge explosion, Price did not have his troops investigate the condition of the fort until daybreak.
Price's subordinates were furious at the deception and demanded to pursue the escaping Union troops. But Price demurred. He had lost over ten percent of his army and three days in the fruitless exercise. His troopers mounted up and resumed their advance northward. However, the dream of taking St. Louis was now gone for Price.
Also on the grounds of the historic site is a museum and interpretive center, which is free and open to the public seven days a week (closed Mondays in winter). A 25 minute film about the battle is shown regularly, as well as a 15 minute audio-visual display of the battle in miniature. The museum includes artifacts from the battle as well as from the war in general.