Throughout 1860, Buford and his fellow soldiers had lived with talk of secession and the possibility of civil war until the Pony Express brought word that Fort Sumter had been fired upon in April 1861, confirming secession as fact.
As was the case with many West Pointers, Buford had to choose between North and South.
Based on his background, Buford had ample reason to join the Confederacy.
He was a native Kentuckian, the son of a slave-owning father, and the husband of a woman whose relatives would fight for the South, as would a number of his own.
On the other hand, Buford had been educated in the North and come to maturity within the Army.
His two most influential professional role models, Colonels William S. Harney and Philip St. George Cooke, were Southerners who elected to remain with the Union and the U.S. Army.
He loved his profession and his time on the frontier had snapped the ties that drew other Southerners home.

John Gibbon, a North Carolinian facing the same dilemma, recalled in a post-war memoir the evening that John Buford committed himself to the Union:
One night after the arrival of the mail we were in his (Buford's) room, when Buford said in his slow and deliberate way "I got a letter from the Governor of Kentucky.
He sent me word to come to Kentucky at once and I shall have anything I want."
With a good deal of anxiety, I (Gibbon) asked "What did you answer, John?"
And my relief was great when he replied "I sent him word I was a Captain in the United States Army and I intended to remain one!"

In November 1861, Buford was appointed Assistant Inspector General with the rank of major, and, in July 1862, after having served for several months in the defense of Washington, was raised to the rank of brigadier general of volunteers.
In 1862, he was given his first position, under Major General John Pope, as commander of the II Corps Cavalry Brigade of the Union Army of Virginia, which fought with distinction at the Second Battle of Bull Run.
Buford personally led a charge late in the battle, but was wounded in the knee by a spent bullet.
The injury was painful, but not serious, although some Union newspapers reported that he had been killed.
He returned to active service, and served as chief of cavalry to Major Generals George B. McClellan and Ambrose E. Burnside in the Army of the Potomac.
Unfortunately, this assignment was nothing more than a staff position, and he chafed for a field command.
In McClellan's Maryland Campaign, Buford was in the battles of South Mountain and Antietam, replacing Brigadier General George Stoneman on McClellan's staff.
Under Major General Joseph Hooker in 1863, however, Buford was given the Reserve Brigade of regular cavalry in the 1st Division, Cavalry Corps of the Army of the Potomac.

After the Battle of Chancellorsville, Major General Alfred Pleasonton was given command of the Cavalry Corps, although Hooker later agreed that Buford would have been the better choice.
Buford first led his new division at the Battle of Brandy Station, which was virtually an all-cavalry engagement, and then again at the Battle of Upperville.

In the Gettysburg Campaign, Buford, who had been promoted to command of the 1st Division, is credited with selecting the field of battle at Gettysburg.
On June 30, Buford's command rode into the small town of Gettysburg.
Very soon, Buford realized that he was facing a superior force of rebels to his front and set about creating a defense against the Confederate advance.
He was acutely aware of the tactical importance of holding the high ground south of Gettysburg, and so he did, beginning one of the most important battles in American military history.
His skillful defensive troop dispositions, coupled with the bravery and tenacity of his dismounted men, allowed the I Corps, under Major General John F. Reynolds, time to come up in support and thus maintain a Union foothold in tactically important positions.
Despite Lee's barrage attack of 140 cannons and a final infantry attack on the third day of the battle, the Union army won a strategic victory.
 The impor
Throughout 1860, Buford and his fellow soldiers had lived with talk of secession and the possibility of civil war until the Pony Express brought word that Fort Sumter had been fired upon in April 1861, confirming secession as fact. As was the case with many West Pointers, Buford had to choose between North and South. Based on his background, Buford had ample reason to join the Confederacy. He was a native Kentuckian, the son of a slave-owning father, and the husband of a woman whose relatives would fight for the South, as would a number of his own. On the other hand, Buford had been educated in the North and come to maturity within the Army. His two most influential professional role models, Colonels William S. Harney and Philip St. George Cooke, were Southerners who elected to remain with the Union and the U.S. Army. He loved his profession and his time on the frontier had snapped the ties that drew other Southerners home.
John Gibbon, a North Carolinian facing the same dilemma, recalled in a post-war memoir the evening that John Buford committed himself to the Union:
One night after the arrival of the mail we were in his (Buford's) room, when Buford said in his slow and deliberate way "I got a letter from the Governor of Kentucky. He sent me word to come to Kentucky at once and I shall have anything I want." With a good deal of anxiety, I (Gibbon) asked "What did you answer, John?" And my relief was great when he replied "I sent him word I was a Captain in the United States Army and I intended to remain one!"
In November 1861, Buford was appointed Assistant Inspector General with the rank of major, and, in July 1862, after having served for several months in the defense of Washington, was raised to the rank of brigadier general of volunteers. In 1862, he was given his first position, under Major General John Pope, as commander of the II Corps Cavalry Brigade of the Union Army of Virginia, which fought with distinction at the Second Battle of Bull Run. Buford personally led a charge late in the battle, but was wounded in the knee by a spent bullet. The injury was painful, but not serious, although some Union newspapers reported that he had been killed. He returned to active service, and served as chief of cavalry to Major Generals George B. McClellan and Ambrose E. Burnside in the Army of the Potomac. Unfortunately, this assignment was nothing more than a staff position, and he chafed for a field command. In McClellan's Maryland Campaign, Buford was in the battles of South Mountain and Antietam, replacing Brigadier General George Stoneman on McClellan's staff. Under Major General Joseph Hooker in 1863, however, Buford was given the Reserve Brigade of regular cavalry in the 1st Division, Cavalry Corps of the Army of the Potomac. 
After the Battle of Chancellorsville, Major General Alfred Pleasonton was given command of the Cavalry Corps, although Hooker later agreed that Buford would have been the better choice. Buford first led his new division at the Battle of Brandy Station, which was virtually an all-cavalry engagement, and then again at the Battle of Upperville.
In the Gettysburg Campaign, Buford, who had been promoted to command of the 1st Division, is credited with selecting the field of battle at Gettysburg. On June 30, Buford's command rode into the small town of Gettysburg. Very soon, Buford realized that he was facing a superior force of rebels to his front and set about creating a defense against the Confederate advance. He was acutely aware of the tactical importance of holding the high ground south of Gettysburg, and so he did, beginning one of the most important battles in American military history. His skillful defensive troop dispositions, coupled with the bravery and tenacity of his dismounted men, allowed the I Corps, under Major General John F. Reynolds, time to come up in support and thus maintain a Union foothold in tactically important positions. Despite Lee's barrage attack of 140 cannons and a final infantry attack on the third day of the battle, the Union army won a strategic victory.  The impor
John Buford