In response, and partly to protect the new telegraph line, the Army began increasing its presence in the region in 1861 by sending a detachment to guard Guinard's bridge.

The will was discovered in 1866 and Louis P Guinard stated that he was advised by Major Bullock, sutler at Ft. Laramie, that the will left him as sole owner of the property and that he should remain and hold possession of it.

They had previously scouted the area and selected it because the soldiers there were not in the small trading post stockade of 14-foot pine logs but camped in tents.

Adam Smith Leib, escorted by 1st Lt. Henry C. Bretney and six (some accounts say 10)[6] troopers of Company G, 11th Ohio Volunteer Cavalry, arrived from Sweetwater Station en route to Fort Laramie for supplies and a long-overdue payroll.

[7] Bretney, who had succeeded to command of Company G on February 13 when its captain, Levi M. Rinehart, had been accidentally killed by a drunken trooper during a skirmish, was not on good terms with Anderson.

On his arrival at Platte Bridge on July 16, the Kansan had replaced Bretney as post commander and ordered Company G to relocate to Sweetwater Station, escorting the same wagon train now returning from there.

Collins and a small detachment of 25 men of the 11th Kansas crossed the Platte Bridge at a walk, then formed into a column of fours and rode west along the north bank at a trot to drive off any hostile Indians.

[11] The Indians had concealed large bands of warriors near the bridge and over the crest of the hills, possibly as many as a thousand Lakota, Cheyenne and Arapaho.

[4] Bretney in a rage returned to the stockade and accused the Kansas officers of cowardice when Anderson refused to allow a larger force and the howitzer to attempt another relief.

Anderson placed Bretney under arrest and turned over the post's defenses to Leib, who had the garrison throw up an embrasure and dig rifle pits to protect the howitzer at the south end of the bridge.

During the morning the attacking force destroyed a thousand feet of telegraph wire on the line to Fort Laramie before Anderson thought to request reinforcements, then drove off the detail sent to repair it, killing another trooper.

[15] However Army accounts state that the wagons were forced into a hollow where they held out for four hours, using fire from Spencer rifles to repel assaults until a large group closed on foot and overwhelmed the defenders, killing all.

The wagons were burned at approximately 3:00 p.m. Corporal James A. Shrader and four troopers, sent as scouts by Custard to investigate the sound of the howitzer firing, were cut off and pursued by a hundred Cheyenne led by the brother of Roman Nose, Left Hand, who was killed in the running fight.

Two Shoshone scouts were paid to take a message requesting reinforcements to the next telegraph station east, but the attacking force broke up before relief arrived.

Historian Robert Utley placed combined Indian casualties in all the July forays around Platte Bridge Station as 60 killed and 130 wounded.

In early December members of a living history group portraying a company of the 3rd US Infantry host a historical reenactment at the site.