Maybe something to think about (WDS or another publisher?)

[krmiller]

On the march at 4 abreast a 125 yard hex can hold about 500 men, since the average regiment would normally be 3-400 men say 1 regiment plus wagon per hex. At 1750 yards per mile say 14 hexes per mile or about 5-6000 men, about the average sized division.

Deployed for battle is another story, at Gettysburg Longstreet's Corps of Hood & McClaws divisions and 2 battalions of artillery, close to 15,000 men, were deployed in an area about 1.5 miles long and a half mile deep.