Beverley Dock, at the foot of the lane marked here in Philipstown, became Benedict Arnold’s escape point on September 25, 1780. Arnold was then the American commander responsible for West Point and the Hudson Highlands. Secretly, however, he had negotiated with British officers to surrender the fortress, its garrison, stores, and strategic river position. His flight from this landing completed his personal defection after the larger conspiracy suddenly unraveled.

The plot depended on Major John André, the British adjutant general and intelligence officer who met Arnold near the Hudson. Unable to return safely to the sloop of war Vulture, André traveled overland in civilian clothes carrying papers that described West Point’s defenses. American militiamen captured him near Tarrytown on September 23. The documents were sent up the chain of command, though delays and confused handling temporarily gave Arnold an opportunity to escape.

On the morning of September 25, Arnold was at his headquarters in the confiscated Beverley Robinson House, expecting George Washington to arrive for breakfast. A message warned him that André had been taken. Recognizing that exposure was imminent, Arnold left abruptly, rode downhill to the river, and ordered a boat crew to take him to the Vulture. He reached the British ship before American officers understood the full situation and could close the river.

Arnold attempted to persuade or compel the boatmen to enter British service, but they eventually returned. He received a British commission and money, though far less than he would have gained had West Point fallen. André was tried as a spy and hanged on October 2. Washington strengthened the fortress and confronted the devastating fact that a trusted major general had tried to deliver one of the Continental Army’s most important positions to the enemy.

The Hudson made both conspiracy and escape possible. West Point’s bends and heights controlled a crucial north–south corridor; the Vulture provided communication with British-held New York; riverside houses, docks, roads, and small boats formed the network connecting them. The marker identifies a precise movement within that landscape. It does not mark the André meeting place or the capture site, but the final American ground Arnold crossed before reaching British protection.

The original dock and shoreline context have changed, so the plaque functions as a geographic anchor rather than a preserved stage set. From this place, visitors can trace the short physical distance between headquarters, river, and escape vessel and appreciate how narrow the margin was. Arnold’s Flight Marker records no battle, yet it marks a decisive intelligence failure, a hurried escape, and the moment an admired American commander became an active British officer.