In October of 1777, George Washington declared an "All Colony Thanksgiving" because he was feeling really good due to:

AThe victory over Saratoga
BHis Mt. Vernon home got finished
CEstablishing the 13 original colonies

Verified Answer :

DefinitelyThe victory over Saratoga

Answer: (a) The victory over Saratoga

The Continental Congress recommended that the colonies observed a day of thanksgiving in 1777 in celebration of the U.S. victory in the Battle of Saratoga. George Washington, then the commander-in-chief of the Continental forces, issued the order to set aside December 18 for this purpose. This tradition continued through 1784.