The Battle of Birch Coulee, fought between September 2 and 3, 1862, was the worst defeat the United States suffered and the Dakotas’ most successful engagement during the U.S.-Dakota War of 1862. Over thirty hours, approximately 200 Dakota soldiers pinned down a Union force of 150 newly recruited U.S. infantry and cavalry soldiers and civilians from the area, holding them until reinforcements arrived.

The U.S.-Dakota War of 1862, a formative event in the history of Minnesota, was initiated by factions of the Dakota, who had endured years of repeatedly broken promises by the federal government and were starving as they waited for annuity payments owed to them. The Battle at Birch Coulee was the longest battle of the war.

After some skirmishes with Union soldiers and attacks on civilian settlers, Dakota fighters, under the command of Little Crow, split off into two groups. The first, commanded by Little Crow, went east. The other group, under Gray Bird, moved toward New Ulm, with the idea of taking the city. With him were chiefs Red Legs, Big Eagle, and Mankato. On their way there, they encountered a camp of U.S. soldiers in a strategically weak position at Birch Coulee. Putting aside their aims for New Ulm, the 200 Dakota fighters decided to attack at dawn on September 2.

Two days earlier, on August 31, approximately 150 men under the command of Joseph Brown left Fort Ridgely to bury dead bodies from earlier attacks and seek out any survivors. Brown had been a successful trader, but he was not an experienced military commander. After a day on burial detail, the force camped for the night on the prairie. The next day, the party continued their grisly task and discovered Justine Kreigher, a woman who had been wounded in earlier fighting. That night, Hiram Grant selected a camping site near water at Birch Coulee while Brown was away searching for signs of Dakota in the area. While soldiers under his command felt their position vulnerable, Grant was confident that there were no Dakota around.

The site would prove to be strategically unsound for the Union forces. The campsite was a short but significant distance from fresh water, and it was near trees and high grass that would hide hostile Dakota soldiers. Grant also placed guard posts too close to camp for a warning to do any good. When morning arrived, the Dakota took advantage of the Union camp’s weaknesses and attacked. Though spotted by a guard, they were able to severely damage the federal force within the first few minutes of the fighting. Most U.S. casualties occurred during this critical time. The Dakota poured gunfire into the camp and killed nearly all of the horses there. Though he ultimately survived the battle, Brown was shot in the neck during these opening moments, and Joseph Anderson took charge of the defense. U.S. soldiers dug shallow holes and used horse carcasses to shield themselves from the bullets.

Somewhat surprised by a Union force larger than they expected, the Dakota decided to wait while the sun and lack of water did their work on the besieged troops, rather than risk their own soldiers on a frontal assault. The U.S. soldiers spent the day pinned down by desultory fire and baking under the hot sun.

Hearing what his scouts thought might be the sound of gunfire, Colonel Henry Sibley sent Colonel Samuel McPhail with 240 men from Fort Ridgely to see what was happening. McPhail arrived at the siege hours into the battle, but was fooled by a ruse. Chief Mankato and a small force of Dakota soldiers convinced McPhail that he faced several hundred Dakota fighters. Rather than engage the fight, McPhail chose to camp two miles away and send for help from the fort.

The next day, Sibley himself brought relief for the besieged men. When he approached with a large force, the Dakota fighters retreated, though they had severely injured their opponents. The U.S. casualties in the battle were thirteen dead, almost fifty wounded, and ninety horses killed. Dakota accounts only mention two deaths among their soldiers.

For more information on this topic, check out the original entry on MNopedia.