Ambrose Everett Burnside (May 23, 1824 – September 13, 1881) was an American army officer and politician who became a senior Union general in the Civil War and three-time Governor of Rhode Island, as well as being a successful inventor and industrialist.

He was responsible for some of the earliest victories in the Eastern theater, but was then promoted above his abilities, and is mainly remembered for two disastrous defeats, at Fredericksburg and the Battle of the Crater (Petersburg). Although an inquiry cleared him of blame in the latter case, he never regained credibility as an army commander.

Burnside was a modest and unassuming individual, mindful of his limitations, who had been propelled to high command against his will. He could be described as a genuinely unlucky man, both in battle and in business, where he was robbed of the rights to a successful cavalry firearm that had been his own invention. His spectacular growth of whiskers became known as "sideburns," deriving from the two parts of his surname.