A commanding General (Lee) who had built-up essential momentum after his string of victories in Summer '62.
An enemy General who was looking increasingly hesitant and reluctant to attack.
A good chance that Britain and France would grant official recognition to the Confederacy - if they succeeded in their invasion of the North.
(And a few spies in the Union camp - though the other side may have had the same.)
By chance, McClellan had acquired a set of Lee's orders, revealing that his divisions were widely separated, and could be destroyed piecemeal.
More money
The offensive was launched by the South, not the North. The particular advantage enjoyed by the North was a set of Lee's orders that a Confederate officer had lost in the field, and were shown to McClellan. These orders revealed that Lee's divisions were widely separated, and could be destroyed piecemeal. McClellan did not move fast enough to exploit this advantage to the full, but Lee had to concentrate his forces in a hurry and fight in a location that was unfavourable to him.
It was the South that had the advantages - a superior General and an army in high morale - until a Confederate officer accidentally dropped a set of Lee's orders in the field, where they were found and shown to McClellan, who was then able to exploit the wide gaps in the Confederate lines. Only the presence of a Confederate spy in his camp (able to alert Lee) prevented him from destroying the Army of Northern Virginia.
Maryland is in North America, specifically in the United States.
maryland
The Battle of Boonsboro (South Mountain) was fought in Washington and Frederick counties in Maryland September 14, 1862. It was a part of Lee's Maryland Campaign which culminated in the bloody Battle of Antietam (Sharpsburg) September 17 1862. See the following link for more about the battle.
Maryland, North Carolina, Tennessee, Kentucky, West Virginia
Yes. Maryland is one of the 48 continental United States. Located on the east coast of the USA, Maryland is indeed in North America.
Montana is on the Canadian border and is much farther north than Maryland.
Maryland,Virginia,Georgia,North Carolina, and South Carolina
Maryland