The battle occurred after a group of Dakota warriors followed a U.S. burial expedition, including volunteer infantry, mounted guards and civilians, to an exposed plain where they were setting up camp.

That night, 200 Dakota soldiers surrounded the camp and ambushed the Birch Coulee campsite in the early morning, commencing a siege that lasted for over 30 hours, until the arrival of reinforcements and artillery led by Colonel Henry Hastings Sibley.

Sibley concluded that it was safe to send an expedition to bury the dead at the Lower Sioux Agency and near Beaver Creek and Birch Coulee,[2] and ascertain what had happened to Colonel John S. Marsh and his soldiers on August 18.

Over 100 men followed Taoyateduta Little Crow and Walker Among Sacred Stones (Tukanmani) into the "Big Woods" west of Hutchinson, where they planned to hit Cedar Mills for flour and disrupt Sibley's supply trains heading to Fort Ridgely.

[2] Meanwhile, Gray Bird (Zitkahtahhota), Mankato, Big Eagle (Wamditanka) and others would lead more than 200 soldiers, plus many women and wagons, south along the river with the objective of collecting plunder left behind in Little Crow's village and in New Ulm, which had been abandoned.

[2] They were accompanied by approximately 20 civilians who had asked to join the burial party, including former Indian agent Major Joseph R. Brown, who would be able to lend his expertise in the Dakota "character and country.

"[5][6] Brown himself was looking for his wife and children, unaware that they were alive and safe in the "friendly" Dakota camp with Gabriel Renville (Ti'wakan) after being rescued by Akipa on August 23.

Symptomatic of the challenges in coordinating the volunteer militia, the question of whether Grant or Brown was actually in command of the expedition became a topic of major controversy in the disastrous aftermath of the battle, continuing among historians today.

After crossing the river by horse and ferry and receiving the "all clear" from several skirmishers who had gone ahead, the group advanced up the hill and entered the ruins of the agency, where they stopped to bury more bodies.

Also, since most of the burial detail felt themselves safe, they failed to take precautions against attack such as digging entrenchments and posting sentries far enough from camp to give ample warning.

One of Anderson's men, mixed-blood soldier Joseph Coursolle (Hinhankaga), later recounted, "We were dog tired, but in spite of 'Major' Brown's assurance, many of us, mostly those with Sioux blood, dug shallow holes to lie in.

"[7] Meanwhile, the Dakota party including Gray Bird, Mankato, Big Eagle and Red Legs and more than 200 men had reached the Lower Sioux Agency in the afternoon.

The soldiers had, however, gone to sleep with their muskets loaded, and many were able to return fire, crouching behind the fallen horses they used as barricades, and driving back the Dakota warriors who approached the wagons.

Coursolle recalled, "The unscathed horse seemed to have a charmed life and we clung to a faint hope that somebody might mount him and dash through the besieging braves to summon relief from Fort Ridgely.

[8] At least two men in the campsite completely panicked, ran out and were shot down by the Dakota, including Peter Boyer, one of Anderson's "mixed-blood" mounted guards whom he later accused of deserting,[10] and Jonathan Henderson, a settler who had buried his wife and children the day before.

Robert K. Boyd, who was seventeen years old himself at the time, wrote, "It should be considered that our men were new recruits, nearly all ignorant as to the use of arms and carrying army rifles which were strange to them; not one of the guns ever having been fired at a target.

We could crawl through the grass and into the coulie and get water when we wanted it, and after a few hours our women crossed the river and came up near the bluff and cooked for us, and we could go back and eat and then return to the fight.

[3]: 309 Back at Fort Ridgely, which was about sixteen miles away, Colonel Sibley had been alerted to the sound of gunfire coming from Birch Coulee, and sent out a relief party of 240 soldiers with two six-pounder guns.

On the topic of Dakota reinforcements, Big Eagle stated: "Late in the day some of the men who had been left in the villages came over on their horses to see what the trouble was that the camp had not been taken, and they rode about the prairie for a time, but I do not think many of them got into the fight.

Instead, during the Battle of Birch Coulee, the Dakota soldiers following Little Crow and Tukanmani divided up and attacked Hutchinson and Forest City, burning the towns down.

The loss of all the horses on the Birch Coulee campsite, combined with mounts lost by Colonel McPhail, "literally destroyed Sibley's precious little cavalry.

Frustrated at the lack of trained soldiers, horses and ammunition available to him, Sibley feared another ambush and was cautious about acting prematurely; he was also conscious that any mistake he made could result in the slaying of the prisoners.

[2] As panic set in within eastern Minnesota, angry newspaper editors accused Sibley of incompetence, expressing frustration that he had underestimated the ruthlessness of the belligerent Sioux and was overly cautious.

Cloud newspaper publisher Jane Swisshelm wrote in a scathing letter to Governor Ramsey: "For God's Sake put some live person in command of the force against the Sioux as Col. Sibley has 100 men or thereabouts in his undertaker's corps.

[1] On the Dakota side, the Battle of Birch Coulee and the Big Woods raids led by Little Crow and Tukanmani on Forest City and Hutchinson strengthened the hostile Mdewakantons' belief that they could defeat the whites.

[13] One of the most significant developments connected with Birch Coulee was that Colonel Sibley left a message for Little Crow – enclosed in a cigar box and attached to a stake in the ground – on the battlefield afterwards, knowing it was likely to be found.

As Little Crow and his soldiers' lodge learned that Sibley's army was growing in number and would likely start marching soon, they broke up camp on September 9 to move further north, only to be repelled by Red Iron, who refused to let them pass.

[3]: 310  On the same day, Captain Anderson presented his report on the battle to Major Joseph R. Brown as "Commander of the Expedition," and deliberately left out any mention of Grant.

In his narrative of the war from a Dakota point of view published on July 1, 1894, in the St. Paul Pioneer Press, Big Eagle (who had been sentenced to death but received a pardon from President Abraham Lincoln) said, "Some years ago I saw Capt.

Casualties:[10] Four bands of Dakota warriors, mainly Mdewakanton and Wahpekute, were at the Battle of Birch Coulee, led by Gray Bird, Mankato, Big Eagle and Red Legs.