I know both the Union and the CSA had Light Divs. but were they any different to any other divisions in their respective armies?
The light Division of the British Army was originally made up of specially trained light infantry regiments (lessons learnt from the AWI) and had an elite status. Was this the case for the American Light Divs during the Civil War?
A.P. Hill's "Light Division" was consituted of the same material as the other divisions in the Army of Northern Virginia. The men liked to think of themselves as special, though, and some commented later that the Light Division was "made of steel, rather than flesh and blood."
Hill took command of a six brigade division (the infantry brigades were from South Carolina, Georgia, North Carolina (2), and Virginia) in the late spring of 1862. The Division was the largest in the Army.
Hill gave it the name "Light Division" when he headed a dispatch from his headquarters on June 1, 1862 simply "Headquarters, Light Division." Possible reasons he named it the Light Division include a desire to differeniate his command from that of D.H. Hill or it's possible that Powell (a lifelong student of military history) was inspired by the British "Light Brigade." It also could have been meant in jest as it was the biggest division in the Army. The men thought the name reflected the fact that "we are lightly armed, lightly fed, but march rapidly, fight frequently."
Hill's Light Division was one of the best in Lee's Army, but the troops were not specially trained or any different from the ones you'd find in the rest of the ANV.
I believe the Union Light Division was a part of the Sixth Corps, Army of the Potomac. It was basically a single brigade commanded by Col. Hiram Burnham at Chancellorsville. It was organized around the time of the battle of Fredericksburg by General Pratt. The name seems to have passed out of existence officially after Chancellorsville.
A.P. Hill's Light Division is far and away the more famous of the two. If you say "Light Division" to a Civil War student, he/she will think of A.P. Hill's Division.