Warning! SPOILERS about Outlander, season 7, episode 4, and the Outlander books ahead.
Cornelius Harnett's return to Outlander season 7, episode 4 meant bad news for Jamie and Claire's Scotland plans, but their new destination of Fort Ticonderoga anticipates the action that will fill their future, given the fort's historical importance in the American Revolutionary War. Jamie's affiliation with the Sons of Liberty proved fateful. If he hadn't saved Harnett in Outlander season 6, he wouldn't have been called to join the cause. Harnett forcing his hand by threatening conscription puts Jamie and Claire in the midst of yet another fight against the British, guaranteeing crucial developments for Outlander season 7 that will surely bring chaos to Jamie and Claire's lives.
Outlander season 7, episode 4 secured Fort Ticonderoga as more than Jamie and Claire's destination. Harnett's news about General Schuyler needing more men at the fort evidently reached also Rachel and Denzell Hunter, as Outlander season 7 just introduced the new characters before sending them along William Ransom towards the fort. What happens at Fort Ticonderoga in An Echo in the Bone will cement the connection between the Hunters and the Frasers, but Jamie and Claire's presence there establish their centrality within the American Revolutionary War, as both the Battle of Fort Ticonderoga and the Siege of Fort Ticonderoga were crucial historical events.
Situated at the south end of the narrow Lake Champlain in New York, Fort Ticonderoga's strategic position gave it control of the La Chute River, which still connects Lake Champlain to Lake George. Built between 1755 and 1757 by the French and originally known as Fort Carillon, the star-shaped fort was strategically important in the Seven Years' War. The fort's strategic position is even acknowledged in the name, as Ticonderoga comes from the Iroquois word meaning between two waters. However, as Outlander highlighted, it's during the American Revolutionary War that Fort Ticonderoga's importance is taken to a whole other level.
While Outlander season 7 only introduced Fort Ticonderoga after the continental army was already in control of it, the Battle of Fort Ticonderoga was fundamental in boosting the morale of the American revolutionaries (via History.com). In May 1775, when the fort was still under British control, the Green Mountain Boys militia led by Ethan Allen and Benedict Arnold captured the British garrison and acquired their artillery, among which cannons were fundamental in ending the Siege of Boston in the same year. Because of its strategic location, Fort Ticonderoga was also used as a staging area for the Continental Army before attacking British-held Canadian territories.
Another key event of the American Revolutionary War happening there was the 1777 Siege of Fort Ticonderoga, which is bound to happen soon in Outlander season 7, given Cornelius Harnett's speech to Jamie and the show's timeline. Led by General John Burgoyne, the British Army managed to force the Continental Army's hand by placing a cannon on Mount Defiance, essentially pushing General St. Clair and his small army to evacuate the fort. The surrender of Fort Ticonderoga was a significant loss for the revolutionaries, as it was believed to be virtually inexpugnable. The Redcoats only definitively abandoned Fort Ticonderoga in November 1777 after General John Burgoyne surrendered at Saratoga.
