This Day in History: George Washington drives the British out of Boston

On this day in 1776, the British army evacuates Boston. It was the culmination of an American effort that had begun many months earlier.

The City of Boston had been under siege by the Americans since April 1775. As the months wore on, a colonel in George Washington’s army, Henry Knox, had an idea: Why not retrieve the British cannons and artillery that could be found at Forts Ticonderoga and Crown Point? Those forts had been captured by the Americans, and the cannons were available, assuming someone could make the trip with them.

The journey would be no easy feat. The forts were hundreds of miles away, near Lake Champlain in New York. By then, it was winter. Travel would be rough. But Knox said that he could do it, and Washington put him in charge of the expedition.

Knox and his brother left Cambridge on November 16, 1775. They arrived at Fort Ticonderoga several weeks later, on December 5. Knox selected 58 mortars and cannons to haul back to Boston. Historian David McCullough reports that the collective weight of these items was at least 120,000 pounds!

Knox’s plan was to ship the cannons down Lake George before beginning the laborious trip overland: nearly 300 miles. He had hired men to help him, but the trip down the lake was only an hour old when they began to run into numerous difficulties: Ice complicated the voyage. The men had to row hard in the face of rough winds. One ship sank and was bailed out.

Problems continued once they hit land. Knox had arranged for sleds and oxen to help haul the cannons, thinking that there would be snow to assist their journey. But there was no snow! Okay, so there was no snow **at first**—then there was a blizzard and **too much** snow! The convoy overcame other difficulties, too: A cannon broke through ice on the Hudson and sank. Fortunately, it was retrieved. At another point in the journey, the men had to get the cannons down steep hills. Well, you know what happens to heavy cannon being pulled down a hill, right?! That wasn’t going to work, so Knox’s men devised a system whereby the sleds were tethered to trees at the top of the hill. These tethers kept the sleds from sliding down too quickly.

Amazingly, Knox’s procession reached Washington’s army safely on January 18. McCullough describes the scene: “Knox’s ‘noble train’ had arrived intact. Not a gun had been lost. Hundreds of men had taken part and their labors and resilience had been exceptional. But it was the daring and determination of Knox himself that had counted above all.”

And the cannons changed everything! Now Washington had an advantage that he did not have before.

Washington decided to occupy and fortify Dorchester Heights, overlooking the city. The British lines would be well within range of the new American cannons, putting the British at a disadvantage. Washington determined to accomplish this feat in the middle of the night, taking the British by surprise.

The story of Dorchester Heights is enough to fill its own post! For now, suffice it to say that the fortification of Dorchester Heights was another amazing feat for Washington’s relatively untrained army. The fortifications had to be built in advance, as they could not be constructed in one night atop an icy hill. Then the pre-constructed fortifications and the cannons had to be dragged up the steep hill at Dorchester Heights, quickly and in secrecy.

The Americans managed the task in one night. On the morning of March 5, the British awoke to a surprising sight: American cannons were now staring down at them from the newly fortified Dorchester Heights. Amazing!

As a result, on March 17, the British finally evacuated the City of Boston, restoring the city to American control.

P.S. The attached picture shows Knox’s journey with the oxen and sleds pulling the cannon to Boston.