Lyman Kidder was born at Braintree, Vermont, on 31st August, 1842. He joined the army in 1861 and served in the Curtis Horse Regiment and the 5th Iowa Cavalry. Kidder then joined the 1st Minnesota Mounted Rangers and fought in the battles of Big Mound (24th July, 1863), Buffalo Lake (July, 26, 1863) and Stony Mound (28th July, 1863).
In August 1864 Kidder joined the Minnesota Cavalry and for the next two years was stationed at Fort Ripley. In January 1867 Kidder was commissioned a second lieutenant of the 2nd Cavalry. He served in Kansas and took part in the Indian Wars.
On 29th June, 1867, Kidder, with an Indian scout, and ten enlisted men, was ordered to take dispatches from General William Sherman to General George A. Custer, who was camped on the Republican River in Nebraska. Kidder never arrived and on 12th July, Custer's scout, Will Comstock, found the mutilated bodies of the Kidder party. It was later discovered the men were killed by a war party of Cheyenne and Sioux warriors.