Why did General Charles Cornwallis retreat from the Carolinas and march north into Virginia?

General Charles Cornwallis campaign in Carolinas was not successful and many men in his army are killed. The Loyalist elements in the area are defeated by the Americans.

Explanation:

Cornwallis and his troops marched to Wilmington. Because of the lack of loyalist support the conquest of virginia impossible, and he established army in an unfortified, low lying, poor defensive position at yorktown.

His army was sick and wounded the Americans gained strength everywhere in the area.

Loyalist supporters in the area were defeated.