Nominated to the United States Military Academy by Congressman Robert Schenck, he graduated in 1852, ranking near the bottom of his class.

These wilderness skills led one of his aides to liken him to Daniel Boone, and more importantly, provided a strong foundation for his abilities to understand, navigate and use Civil War landscapes to Union advantage.

When the Civil War broke out, Crook accepted a commission as Colonel of the 36th Ohio Infantry and led it on duty in western Virginia.

After the Union Army's defeat at Second Bull Run, Crook and his regiment were attached to the Kanawha Division at the start of the Maryland Campaign.

To open the spring campaign of 1864, Lieutenant General Ulysses S. Grant ordered a Union advance on all fronts, minor as well as major.

Grant instructed Crook to march his force, the Kanawha Division, against the railroad at Dublin, Virginia, 140 miles (230 km) south of Charleston.

When these actions were accomplished, along with the destruction of the salt works, Crook was to march east and join forces with Major General Franz Sigel, who meanwhile was to be driving south up the Shenandoah Valley.

The way was narrow and steep, and spring rains slowed the march as tramping feet churned the roads into mud.

On the other side of the meadow, the land rose in another spur of the mountain, and there Jenkins' rebels waited behind hastily erected fortifications.

The barrier caused little delay and the Yankee infantry stormed up the hill and engaged the rebel defenders at close range.

While the fight at Cloyd's Mountain was going on, a train pulled into the Dublin station and disgorged 500 fresh troops of General John Hunt Morgan's cavalry, which had just diverted Averell away from Saltville.

The reinforcements halted the rout, but Colonel Hayes, although ignorant of the strength of the force now before him, immediately ordered his men to "yell like devils" and rush the enemy.

The next morning the main body set out for their next objective, the New River bridge, a key point on the railroad, a few miles to the east.

Seeing that there was little danger from the rebel cannon, Crook ordered the bridge destroyed, and both sides watched in awe as the structure collapsed magnificently into the river.

General Crook, supplies running low in a country not suited for major foraging, now entertained second thoughts about his orders to push on east and join Sigel in the Shenandoah Valley.

At Dublin he had intercepted an unconfirmed report that General Robert E. Lee had beaten Grant badly in the Wilderness, which led him to consider whether the Confederate commander might not soon move against Crook with a vastly superior force.

[10] The official VIII Corps of the Union Army was led by Lew Wallace during this time and its troops were on duty in Maryland and Northern Virginia.

[11] Crook led his corps in the Valley Campaigns of 1864 at the battles of Opequon (Third Winchester), Fisher's Hill, and Cedar Creek.

In February 1865 General Crook was captured by Confederate raiders at Cumberland, Maryland, and held as a prisoner of war in Richmond until exchanged a month later.

In 1873, Crook was appointed brigadier general in the regular army, a promotion that passed over and angered several full colonels next in line.

By 0830, the Sioux and Cheyenne had hotly engaged Crook's Indian allies on the high ground north of the main body.

Heavily outnumbered, the Crow and Shoshone scouts fell back toward the camp, but their fighting withdrawal gave Crook time to deploy his forces.

Historians debate whether Crook's pressing on could have prevented the killing of the five companies of the 7th Cavalry Regiment led by George Armstrong Custer at the Battle of the Little Bighorn.

After briefly linking up with General Alfred Terry, military commander of the Dakota Territory, Crook embarked on what came to be known as the grueling and poorly provisioned Horsemeat March, upon which the soldiers were reduced to eating their horses and mules.

Crook was made head of the Department of Arizona and successfully forced some members of the Apache to surrender, but Geronimo continually evaded capture.

In March, 1886, Crook received word that Geronimo would meet him in Cañon de los Embudos, in the Sierra Madre Mountains about 86 miles (138 km) from Fort Bowie.

[18] After years of campaigning in the Indian Wars, Crook won steady promotion back up the ranks to the permanent grade of Major General.

Cañon Pintado Historic District, 10 miles (16 km) south of Rangely, Colorado, has numerous ancient Fremont culture (0–1300 CE) and Ute petroglyphs, first seen by Europeans in the mid-18th century.

Numerous military references honor him: Fort Crook (1857–1869) was an Army post near Fall River Mills, California, used during the Indian Wars.

Fort Crook (1891–1946) was an Army Depot in Bellevue, Nebraska, first used as a dispatch point for Indian conflicts on the Great Plains.