Jefferson Columbus Davis was a regular officer of the United States Army during the American Civil War, known for the similarity of his name to that of Confederate President Jefferson Davis and for his killing of a superior officer in 1862.
Davis's distinguished service in Mexico earned him high prestige at the outbreak of the Civil War, when he led Union troops through Southern Missouri to Pea Ridge, Arkansas, being promoted to Brigadier General after that significant victory. Following the Siege of Corinth, he was granted home leave on account of exhaustion, but returned to duty on hearing of Union defeats in Kentucky, where he reported to General William "Bull" Nelson at Louisville in September 1862. Nelson was dissatisfied with his performance, and insulted him in front of witnesses. A few days later, Davis demanded a public apology, but instead the two officers argued noisily and physically, concluding in Davis mortally wounding Nelson with a pistol.
Davis avoided conviction due to the shortage of experienced commanders in the Union Army, but the incident hampered his chances for promotion.