Who was the youngest US general ?

Looks like it was George Armstrong Custer but couldn't find out how old he actually was when he became a general. Could not have been very old considering he was only 35 when he died at Little Big Horn.

That's him Kelley.
Bonus points for whoever can come up with his age when he was appointed a general.

Custer was 23 when he was promoted to Brevet Brigadier General on 28 June 1863.

Decided to add a little history. That's what trivia is all about. George Armstrong Custer was promoted to Brevet Major General in 1864. However, brevet rank is strictly honorary rank in peacetime. In wartime, you receive the pay and authority of your brevet rank. When the war ended, Custer went back to his Regular Army rank of Captain, 5th US Cavalry. The highest Regular Army rank he held was lieutenant colonel. He was NOT in command of the 7th Cavalry, he was second in command. Dang! I love this place!

Thanks for the additional information. I feel that it is the additional information, background, relationship to something else, that makes trivia interesting. Yeah, I love it, too. Tell your friends.

Colonel and Brevet Major-General Galusha Pennypacker, U.S.A. (Born Jun 1, 1844)

For his distinguished personal gallantry in this assault, when he was most severely (and it was thought for a time mortally) wounded, and " for gallant and meritorious services during the war," Pennypacker received six brevets or promotions as follows: Brevet brigadier-general U. S. . Volunteers, January 15, 1865; brigadier-general U.S. Volunteers, February 18, 1865; brevet major-general U.S. Volunteers, March 13, 1865; colonel Thirty-fourth (designation changed to Sixteenth) Infantry U.S.A., July 28, 1866; brevet brigadier-general U.S.A., March 2, 1867, and brevet major-general U.S.A., March 2, 1867.

More here on (what else) AnswerPool.

Pennypacker was younger than Custer when he became a Brevet General. If you are counting a Brevet General as a General, Pennypacker beats Custer.