Decades before the establishment of the U.S. Military Academy at West Point, the strategic plateau on the banks of New York’s Hudson River played a crucial part in the American victory in the Revolutionary War.

Both British and Patriot forces understood the Hudson’s vital importance in winning the war. Since the colonies’ primitive roads were difficult to traverse, the river was a liquid highway for efficiently transporting troops, artillery, food and information during the American Revolution. If the British could seize the Hudson, they could sever New England from the rest of the rebellious colonies and choke off the flow of troops and goods.

“After being forced out of Boston, the British were focused on taking New York City, and they concentrated forces in Quebec and Montreal to try and squeeze the Americans from the north and south and cut off the east from the west,” says Colonel Seanegan Sculley, an associate professor of history at the U.S. Military Academy and author of Contest for Liberty: Military Leadership in the Continental Army, 1775-1783.

General George Washington believed that West Point, located on a bluff overlooking an S-shaped curve in the Hudson 60 miles north of Manhattan, was the key to holding the river and maintaining the unity of the colonies. Washington called West Point “the most important post in America,” and he feared its loss would result in “the most ruinous consequences.”

From the war’s earliest moments, Washington worried about keeping the Hudson River in Patriot hands. Just weeks after the war ignited at Lexington and Concord, Washington served on a committee tasked by the Continental Congress to assess the river’s defenses. Following the committee’s recommendation, the Continental Congress approved a resolution on May 25, 1775, to erect batteries on each side of the river’s highlands to protect against British naval incursions.

A lack of money, time and experienced military engineers thwarted Washington’s desire to immediately fortify West Point. Instead, work began on Fort Constitution on the opposite bank of the river, and in March 1776, Washington ordered the construction of Fort Montgomery and Fort Clinton to defend a giant iron chain, meant to deter British ships, that spanned the Hudson five miles downriver from West Point.

On October 6, 1777, British General Henry Clinton launched a rear overland attack on the two forts defending the chain in an attempt divert patriot forces engaged at the Battle of Saratoga. In a battle that claimed more than 100 lives, the British destroyed both forts along with the nearly completed Fort Constitution, dismantled the chain and continued upriver to burn the town of Kingston. But with his supply lines overextended, Clinton retreated to New York City, and the patriots reasserted control over the Hudson.

When the patriots set out to rebuild and strengthen the Hudson’s defenses, Washington ensured it included fortifications on West Point, where the river is at its narrowest and deepest south of Albany. There, British ships would be forced to navigate a nearly 90-degree turn while negotiating tidal currents and a strong easterly wind. “That is a very difficult maneuver for sailing vessels of the 18th century to make,” Sculley says. And it’s one that would leave British naval forces exposed to cannon fire from the surrounding highlands.

With the Continental Army now possessing greater engineering expertise, Washington commissioned Colonel Tadeusz Kosciuszko to design and oversee the construction of West Point’s fortifications. Having impressed Washington with his defensive strategy at Saratoga, the French-trained military engineer who had arrived from Poland in 1776 devised an integrated complex of forts, redoubts and gun batteries at varying elevations that would deter another overland attack.

“It’s the first time—at least in Western military history—that a decentralized defensive fortification system was devised,” Sculley says. “There were about 30 fortifications, but none of them were contiguous or connected to each other physically. They were all mutually supporting.”

The defenses protected another 65-ton iron chain that spanned 600 yards from West Point to Constitution Island to prevent the passage of enemy ships. Comprised of two-foot-long links more than two inches thick, this "Great Chain" was supported by log rafts and could be disconnected in the center to allow the passage of friendly vessels.

After paying periodic trips to inspect the construction effort, Washington headquartered himself at West Point for four months in 1779 after the British captured a pair of citadels flanking a critical ferry route 12 miles to the south. The British voluntarily relinquished the forts and the ferry crossing in October 1779 as they increasingly focused on a “Southern Strategy.” When the completion of Kosciuszko’s fortress in 1780 further deterred the British from attacking West Point, they made an audacious attempt to seize it without firing a shot.

Even as British attention turned to the South, West Point remained an important strategic target. “West Point provides a problem to Clinton’s north that he can’t ignore. He always had to maintain a large contingent in New York City for fear Washington will launch an assault to take it,” Sculley says. “Clinton can’t afford to lose New York City because the port was absolutely vital to resupplying his army from Great Britain, and this draws men from the southern campaign.”

An opportunity to seize West Point without an attack arose when General Benedict Arnold took command of the fortress on August 3, 1780. Debt-ridden and bitter from being passed over for Continental Army promotions, Arnold agreed to become a turncoat for the Redcoats. In return for his asking price of 10,000 British pounds and a military commission, Arnold plotted to secretly weaken West Point’s defenses, which included a fort named in his honor, before surrendering it to the British.

On September 21, Arnold met with British Major André to discuss plans for the handover. André’s subsequent capture, however, exposed the secret plot. The traitor Arnold fled to a British warship for safety, while the patriots executed the British major.

Throughout the American Revolution, patriot forces never relinquished control of West Point, and it remained one of only two active Army posts after the war’s conclusion. The federal government purchased West Point for $11,085 in 1790, and the U.S. Military Academy was established there in 1802 to educate and train officers in the U.S. Army. Today, West Point is the oldest continuously operated Army post in the United States.