Fortification was begun in June of 1776, and the name Mount Independence was bestowed following the Declaration of Independence. Lieut. Col. Jeduthan Baldwin was the chief construction engineer. Here the exhausted American Army, Northern Department, was stationed after withdrawing from its disastrous Canadian Campaign. Built on a rocky plateau and stoutly fortified, the post was a natural stronghold facing any approaching foe from the north. Within its rugged confines thousands of New Englanders, many succumbing to illness and lack of supplies, were quartered.

Because of its commanding position and formidable battle works, which made it more powerful at the moment than impaired Ticonderoga, it checked for a year a British thrust southward, until at the fall of its companion fortress across the channel it was evacuated in the early morning darkness of July 6, 1777. This critical year of reprieve gave the American forces time to organize farther south, meet and destroy General Burgoyne at Saratoga, win French support, and eventually subdue General Cornwallis at Yorktown, fulfilling the prophecy of the mountain’s name.