[2] The massacre occurred when a large Sioux war party of over 1,500 Oglala, Brulé, and Sihasapa warriors, led by Two Strike, Little Wound, and Spotted Tail attacked a band of Pawnee during their summer buffalo hunt.

The Pawnee were traveling along the west bank of the canyon, which runs south to the Republican River, when they were attacked.

This massacre is by some considered one of the factors that led to the Pawnees' decision to move to a reservation in Indian Territory in what is today Oklahoma, though not all sources agree on its impact in this way.

[7][8]: 356–357 Principal chiefs at the battle were: Among the Pawnee dead were Sky Chief (Tirawahut Lesharo) who was surrounded and killed by the Sioux while skinning a buffalo, and the wife and four children of Traveling Bear, a former sergeant in the Pawnee Scouts who served under Maj. Frank North and a Medal of Honor recipient.

[11] However, smallpox epidemics and increasing Sioux raids on villages beginning in the early 1800s and worsening in the 1830s left the Pawnee in a vulnerable position.

[18]: 232 A Pawnee hunting group—roughly 400 men, women and children[4]: 147 —were located in camp near present-day Trenton on August 4, 1873.

Trail Agent John W. Williamson stayed in the camp with his visitor Lester Beach Platt.

Around the same time in early August, about 700 Brulé Sioux, led by Chief Two Strike, were hunting buffalo in the same area.

[18]: 234  Janis replied that he could not prevent the Sioux from attacking the Pawnee but suggested that the two tribes meet to discuss the matter instead which was ignored.

[13][16] During the day around 1,000 warriors set off for the Pawnee to make a joint, quick attack and prevent the enemy from striking first.

But one of the men, a young man about my age at the time, appeared to be so sincere in his efforts to impress upon me that the warning should be heeded, that I took him to Sky Chief who was in command that day, for a conference.

The following morning August 5, we broke camp and started north, up the divide between the Republican and the Frenchman Rivers.

He recalled our little unpleasantness the night previous and said he did not believe there was cause for alarm, and was so impressed with the belief that he had not taken the precaution to throw out scouts in the direction the Sioux were reported to be.

A Pawnee, who was skinning a buffalo a short distance away but managed to escape, told me how Sky Chief died.

Agent Williamson and either his friend Platt or tribal member Ralph Weeks rode out to arrange a peace council, but bullets forced them back.

[22]: 385 The Pawnee version of the Massacre Canyon battle tells of a few individuals' fate and relates some peculiar incidents.

Women threw hides, dried meat and saddles from the packhorses and the Pawnee started a disorganized retreat.

All through the morning Pawnee survivors found the camp as well as Williamson and Platt, who had made his escape early during the fight.

[21]: 393  Army Dr. David Franklin Powell described the march up the battleground: "We advanced from the mouth of the ravine to its head and found fifty-nine dead Pawnees ...".

Royal Buck wrote to the readers of Nebraska City News that "It was a massacre and nothing more, and near 100 victims are lying on the ground and full two thirds are squaws and pappooses [small Indian children]".

[4]: 148 The Pawnee survivors traveled 80 miles or so to Plum Creek near the Platte where Dr. William M. Bancroft treated the wounded.

[27] A source often quoted is Agent William Burgess, who stated that "20 men, 39 women and 10 children" were killed.

[8]: 351 [20]: 56–57 Following the massacre, the Pawnee received $9,000 for the loss of more than 100 horses, 20 tons of dried meat and all sorts of equipment.

[12]: 998 This incident, in particular, caused the government nationwide to intensify "its efforts to keep the Indians confined to their reservation" in an endeavor to curtail intertribal warfare.

[22]: 385 It was half a century after the battle before the Pawnee and the Sioux smoked the pipe of peace during the Massacre Canyon Pow Wow in 1925.

It stands on a three-acre (1.2 ha) plot, three miles (4.8 km) east of Trenton off U.S. Route 34, after having been moved from its original location overlooking the Republican River valley.

The monument, a large stone obelisk,[33] was constructed from Minnesota pink granite from a quarry in St.

The defeat so broke the strength and spirit of the tribe that it moved from its reservation in central Nebraska to Oklahoma.

The United States government failed to honor the treaty rights guaranteed to the Pawnee, including protection from the Sioux.

[36] The monument is located in a small park area with picnic tables and a visitor center and museum that features exhibits about early pioneers, the tribal customs of the Sioux and the Pawnee people and a gift shop.