Fort Ridgely was built in 1851 in the territory of southern Minnesota. It wasn't much of a fort, but it was the only military post between the Sioux Reservations and the settlers. On August 18, 1862, the Lower Sioux Agency in Renville County, Minnesota, was attacked by Indians. The Native Americans had come to the Agency to barter for the food that had been withheld them until starvation had set in. There was a discussion amongst the leading white men gathered there and the head of the Lower Sioux Agency. The primary Agent was against it, but the other men persuaded him to give the natives a small amount of porkback and flour. The Agent then added that the food would only be delivered to the reservation in the morning and only if the Indians returned to the reservation immediately. Until that point, the well-armed Indians had stood by peacefully in the hot August temperatures. The greatly out-numbered 67 white men gathered there became uncomfortable with the stipulation and began to form small groups to head back to their homes. Inevitable fighting began with some of the warriors pursuing the settlers who left, while the rest remained to fight those who holed up in the Agency building. Within a few hours 20 whites had been killed and 10 captured. Some survivors escaped, heading for Fort Ridgely, while the majority tried to race for their homes and families. The men heading for their homes made plans to assemble in the morning to try to reach the fort.

Mr. J.C. Dickinson, who seems to have been the first to escape, took his family in a wagon to Fort Ridgely, where nobody believed that there had been an attack. More settlers arrived, convincing Captain John S. Marsh, Company B, Fifth Minnesota, that the Agency had been attacked. Marsh ordered Drummer Charles M. Culver, a twelve year old (who would die in 1943, at 93, as Company B's last survivor) to beat the long-roll. About 74 men fell in, amongst who were Captain Marsh, Second Lieutenant Thomas P. Gere, about 4 sergeants, 7 corporals, and about 62 privates. Marsh chose 46 men, along with Indian Interpreter Peter Quinn, to set out for the Agency. Along the way they saw many dead white folk and Indians. Quinn was one of the first of this party killed by Chief White Dog, along with about 10 of the soldiers. By late afternoon, Capt. Marsh had only eleven men left in his command, with twenty-four having been killed. Marsh decided to head back to the fort and tried to take the men across the Minnesota River. Marsh was a strong swimmer, but he was seized by a cramp. Sergeant John F. Bishop, the ranking officer, ordered Privates John Brennan, James Dunn, and Stephen Van Buren to swim for Marsh. Brennan reached him first, and Marsh grabbed Brennan's shoulder but fell off. Marsh drowned and the men saw his body float by in the river. He was about 28 when he died. Sergeant Bishop led the remaining eleven back to the fort. They arrived before midnight and the Battle of Redwood started.

Before Marsh left, he had sent word to Lt. Sheehan, who left Fort Ridgely on August 17, to return with 50 men from Company C, Fifth Minnesota. When Bishop and Sheehan met, they sent Private William J. Sturgis out to warn others, especially Minnnesota Governor Alexander Ramsey about the uprising. Lt. Norman K. Culver, Company B, and others began recruiting volunteers in St. Paul, and they arrived at Fort Ridgely with the "Renville Rangers" as reinforcements. There were about 50 white men under First Lieutenant James Gorman, men who were going to muster into Civil War Service, but went instead to Fort Ridgely with a Harper rifle and three rounds of ammunition each. Altogether, about 70 Minnesota citizens volunteered. About 10 of them were women and others were related to soldiers. Company B membership rose from about 65 to over 200. Some notables include Sutler B.H. Randall, Ordnance Sergeant John Jones, Dr. Alfred Muller, and Major E.A.C. Hatch, an experienced cavalry man who would one day lead Hatch's Battalion, Minnesota Volunteer Cavalry.

On a sunny August 20, Lt. Timothy J. Sheehan, Company C, commanded Fort Ridgely. First Lt. Culver, Company B, was commissary and quartermaster. Eight men were wounded or assigned hospital duty. The Fort was trying to adjust to all the new volunteers that had arrived. Suddenly, a reported 400 Indians attacked the ill-prepared post. First shots killed Private Mark. M. Greer, Co. C, and wounded Corporal William Good, Co. B. Good was shot through the forehead and was declared dead but he managed to live and was eventually discharged for disability on October 24, 1862. Sergeant Bishop commanded the pickets and awaited a native named Little Crow and his warriors but to no avail. Several soldiers were wounded. Private William H. Blodgett, Company B, was wounded in the spinal column but continued to fight. By the end of the battle five soldiers were killed and another 15 wounded.

The next day a thunderstorm struck, so the men and women at the Fort could organize the post and strengthen the defenses. Ordnance Sergeant Jones had three six-pound artillery guns, two twelve pound guns, and one twenty-four pound gun placed. Jones commanded the 24-pounder while Sgts. James G. McGrew and Bishop commanded the twelve pounders. In the 25-mile area around the fort, white settlers had been trying to escape for two days and their bodies and burning homes dotted the landscapes. Indians had been through all the homes and wagons looking for food and goods to bring back to the reservation. Some women and children had been kidnapped, but for the most part, the settlers were killed, many of them barbarically. One account, a narrative of Justina Kreiger tells of a group of settlers who set off on August 18 and were almost all killed, while Mrs. Kreiger did not arrive at the Fort until September 3. It took great effort to save her life as she had sustained many life-threatening injuries and was also almost starved.

On August 22 the sun shone, and proved that the native Americans had put the rainy day to use, as a force of 800 Indians attacked the fort. The first attack was repelled and smaller attacks were attempted throughout the day, mainly to keep the soldiers alert and at their posts. Towards the cooler evening hours, the Dakota warriors staged a more serious attack on the northern side of the fort. Lt. Sheehan was forced to order the buildings on that side to be set afire as he became aware that the Indians were sneaking into the Fort through them. The men watched as the buildings went up in a greenish smoke. The Indians melted back into the darkness. Little Crow and the other native chiefs maintained their siege until August 27, when Colonel Henry H. Sibley arrived with 1,400 trained militia. Colonel Sibley accepted command of this large force, which contained elements of the 5th and 6th Iowa State Militia.

The Native Americans moved on from Fort Ridgely and small groups of them continued to attack various white settlements until September 23, 1862, where a large group were captured at Wood Lake. About 400 were captured, 393 were tried, and 303 sentenced to death. An estimated 500 white people, militia and civilian, were killed in the uprising. President Abraham Lincoln reduced the executions to thirty-nine men. One man was pardoned December 25, 1862 as it came out that he was ten miles away from the deed for which he was convicted. Thirty-eight Dakota men were hanged December 26, 1862, in Mankato, Minnesota, the largest mass-execution in U.S. history.

For rosters of soldiers see: Company B, Fifth Minnesota Infantry, Recollections of the Sioux Massacre, 1909, pages 82-83 Company C, Fifth Minnesota Infantry, Recollections of the Sioux Massacre, 1909, pages 83-84 Renville Rangers, Recollections of the Sioux Massacre, 1909, pages 84-85 Post Locals, page 85 Citizens, 120-121.