Grattan massacre The Grattan Massacre , also known as the Grattan Fight , was the opening engagement of the First Sioux War , fought between United States Army and Lakota Sioux warriors on August 19 , 1854 . It occurred east of Fort Laramie , Nebraska Territory , in present - day Goshen County , Wyoming . A small detachment of soldiers entered a large Sioux encampment to arrest a man accused of taking a migrant ' s cow , although such matters by treaty were to be handled by the US Indian Agent . After one of the soldiers shot Chief Conquering Bear and killed him , the Brulé Lakotas returned fire and killed a total of 29 soldiers , Lieutenant John Grattan , and a civilian interpreter . The massacre , as it was called by the American press , is considered an early , significant event in the Plains Indian Wars . Background . In the late summer of 1854 , about 4 , 000 Brulé and Oglala were camped near Fort Laramie in accordance with the terms of the Treaty of 1851 . On August 17 , a cow belonging to a Mormon traveling on the nearby Oregon Trail strayed and was killed by a visiting Miniconjou named High Forehead . Lt . Hugh Fleming , the senior officer of the small garrison , consulted with the chief , Conquering Bear , to discuss the loss of livestock . Lt . Fleming was evidently unaware , or chose to ignore , that such matters were , by the terms of the Treaty of 1851 , to be handled by the local Indian Agent , in this case John Whitfield , who was due to arrive within days with annuities with which restitution could be made . Aware that the matter did not really concern the military , Conquering Bear attempted to negotiate , offering a horse from his personal herd or a cow from the tribe ' s herd . The cow ' s owner persisted in demanding $ 25 instead . Lt . Fleming asked the Sioux to arrest High Forehead and deliver him to the fort , which Conquering Bear refused ; he had no authority over the Miniconjou and did not want to violate their tradition of hospitality . The day ' s talk ended in stalemate . Second Lieutenant John Lawrence Grattan , of the U . S . 6th Infantry Regiment , a recent graduate of West Point and supernumerary waiting for a vacancy in the regiment , led an armed detachment into the Indian encampment to take custody of High Forehead and bring him back to the fort . Grattan was inexperienced and contemptuous of the Lakotas ' ability as warriors . This was his first encounter with the Sioux . A commander at Laramie later recalled , " There is no doubt that Lt . Grattan left this post with a desire to have a fight with the Indians , and that he had determined to take the man at all hazards . " In Grattan ' s party were a sergeant , a corporal , 27 privates and a French - Native American interpreter named Lucienne Auguste ; the military forces had two artillery pieces in addition to arms . Circumstances . By the time the detachment reached the encampment , Auguste was intoxicated from drinking along the way , as he feared the encounter . Grattan broke his bottle and scolded him . Auguste was not well liked by the Sioux ; he spoke only broken Dakota , and had little grasp of other dialects . As they entered the encampment , he began to taunt the Sioux , calling their warriors women , and saying the soldiers were not there to talk , but to kill them all . James Bordeau , who owned the nearby trading post and observed the encounter , later told of it . Historians estimate the encampment had some 1 , 200 warriors out of the total 4 , 800 population . According to Bordeau , Lt . Grattan began to realize the risk , and stopped to discuss the situation with the trader . Bordeau advised him to talk directly with Conquering Bear and let him handle the situation . Grattan seemed to understand and continued on into the encampment . Going first to the lodge of High Forehead , he ordered him to surrender to the US forces . High Forehead said he would die first . Grattan went to Conquering Bear , saying the Sioux should arrest the guilty party and turn him over . Conquering Bear refused but tried to negotiate , offering a horse as compensation for the cow . Bordeau reportedly said the interpreter Auguste taunted the Sioux , and failed to fully or accurately translate Conquering Bear and Grattan ' s comments , as there seemed to be confusion between them . Conquering Bear asked that the trader Bordeau act as interpreter , as the Sioux trusted him and his language ability . Called by the Sioux , Bordeau rode to the meeting place ; later he said he could see the situation was out of hand . As Grattan pressed Conquering Bear , numerous Sioux warriors moved into flanking positions around the soldiers . Bordeau returned to the trading post , where he told associates to get arms , as a fight was coming . Ending the discussion , Grattan began walking back to his column . A nervous soldier fired his gun , shooting a Sioux . The warriors started shooting arrows while leaders tried to take control . Conquering Bear was mortally wounded and died nine days later near the Niobrara River . The Sioux warriors quickly killed Grattan , 11 of his men , and the interpreter . A group of some 18 soldiers retreated on foot trying to reach some rocks for defense , but they were cut off and killed by warriors led by Red Cloud , who was then a rising War chief within the Sioux . One soldier survived the massacre but later died of his wounds . The 28 killed soldiers are buried at Fort McPherson , Nebraska , while Lt . Grattan is buried in Fort Leavenworth , Kansas . Conquering Bear was the only Lakota who was killed . Bordeau was spared both because he was married to a Brulé Sioux woman , and he had a friendly relationship with the tribes . Aftermath . The enraged warriors " rampaged throughout the night , swearing to attack other whites . " They rode against Fort Laramie the next morning but withdrew ; they looted the trading post but did not harm Bourdeau . On the third day after the US attack , the Brule and Oglala abandoned the camp on the North Platte River and returned to their respective hunting grounds . On the fourth day , the military asked Bourdeau to arrange a burial party . His team went to the scene and found that the slain soldiers had been ritually mutilated . Grattan ’ s body was identified by his watch and was returned to the post for burial . The remains of the troops were interred at the site in the same shallow grave . The soldiers ' remains were later exhumed and re - interred at Fort McPherson National Cemetery , where a white marble monument was erected in their memory . Grattan ' s remains were moved later to Fort Leavenworth National Cemetery in Kansas . A historical marker was later erected about one - half mile from the site of the events ( see photo above . ) The U . S . press called the event the " Grattan Massacre . " Accounts generally ignored the US soldiers ' instigation of the event by shooting Conquering Bear in the back , and Grattan ' s violation of the treaty provisions . When news of the fight reached the War Department , officials started planning retaliation to punish the Sioux . Secretary of War Jefferson Davis characterized the incident as " the result of a deliberately formed plan . " Col . William S . Harney was recalled from Paris in April 1855 and sent to Fort Kearny , where he assembled a command of 600 troops consisting of troops from the 6th Infantry , 10th Infantry , 4th Artillery , and his own 2nd US Dragoons . In all he had four mounted companies led by Lt . Col . Philip St . George Cooke and five companies of infantry under Major Albemarle Cady . They set out on August 24 , 1855 to find and exact retribution on the Sioux . Harney was quoted as saying , " By God , I ' m for battle — no peace . " Warned by Thomas S . Twiss of the Indian Bureau that the army had put a force in the field , half of the Lakota camped north of the Platte came into Fort Laramie to be treated as friendly . The other half , generally led by Conquering Bear ' s successor Little Thunder , remained at large , considering themselves peaceful but aware of Harney ' s approach and continuing to harbor warriors sought by the army . Harney engaged them in the Battle of Ash Hollow ( also known as the Battle of Bluewater Creek ) on September 3 , 1855 , in which U . S . soldiers killed a number of Brulé Sioux in present - day Garden County , Nebraska . The village of 230 persons was caught between an assault by the infantry and a blocking force by the cavalry . Harney returned to Fort Laramie with 70 prisoners . On October 25 the three warriors sought by the expedition surrendered themselves , were held for a year at Fort Leavenworth , then released . Harney ordered the tribes to send representatives to a treaty council at Fort Pierre in March 1856 , where a treaty was signed on terms dictated by the War Department . However Twiss tried to undermine the treaty and Harney had him removed from office without possessing the legal authority to do so . Commissioner of Indian Affairs George W . Manypenny then successfully lobbied the Senate to reject the treaty and Twiss was reinstated . Nevertheless , the specter of Harney restrained the Lakota for nearly ten years . Historians such as Griske believe the following nearly quarter - century of intermittent warfare on the Great Plains was triggered by the Grattan massacre . Others suggest numerous factors , especially US desire for control of lands that were Sioux territory , as to make warfare inevitable .