Knox went to Ticonderoga in November 1775 and moved 60 tons[1] of cannon and other armaments over the course of three winter months by boat, horse, ox-drawn sledges, and manpower along poor-quality roads, across two semi-frozen rivers, and through the forests and swamps of the lightly inhabited Berkshires to the Boston area,[2][3] covering approximately 300 miles (500 km).

Benedict Arnold was a militia leader from Connecticut who had arrived with his unit in support of the siege of Boston; he proposed to the Massachusetts Committee of Safety that Fort Ticonderoga on Lake Champlain in the Province of New York be captured from its small British garrison.

[5] The idea to capture Ticonderoga had also been raised to Ethan Allen and the Green Mountain Boys in the disputed New Hampshire Grants territory in Vermont.

[9] In July 1775, George Washington assumed command of the forces outside Boston,[10] and one of the significant problems which he identified in the nascent Continental Army was a lack of heavy weaponry, which made offensive operations virtually impossible.

[11][12] Knox was a 25-year-old bookseller with an interest in military matters who served in the Massachusetts militia, and he had become good friends with Washington on his arrival at Boston.

[14] Washington's call for the weapons was echoed by the Second Continental Congress, and they issued Knox a colonel's commission in November—although it did not reach him until he returned from the expedition.

[13] The equipment was first carried overland from Ticonderoga to the northern end of Lake George, where most of the train was loaded onto a gundalow (flat-bottomed sailing barge).

This appeared to be a serious setback at first, but Knox's brother William, captain of the gundalow, reported that she had foundered but her gunwales were above the water line, and that she could be bailed out.

[21] On December 17 Knox wrote to Washington that he had built "42 exceeding strong sleds, and have provided 80 yoke of oxen to drag them as far as Springfield",[22] and that he hoped "in 16 or 17 days to be able to present your Excellency a noble train of artillery".

[23] He then set out for Albany ahead of the train, crossed the frozen Hudson River at Glens Falls, and proceeded on through Saratoga to reach Lansingburg on Christmas Day.

There he met with General Philip Schuyler, and the two of them worked over the next few days to locate and send north equipment and personnel to assist in moving the train south from Lake George.

[28] Washington wanted to end the siege, and he formulated a plan to draw at least some of the British out of Boston once the equipment began to arrive, at which point he would launch an attack on the city across the Charles River.

[29][30] These batteries opened fire on Boston on the night of March 2, 1776, while preparations were made to fortify the Dorchester Heights from which cannons could threaten both the city and the British fleet in the harbor.

[34] At the time of the exploit's sesquicentennial (150th anniversary), the State of New York and the Commonwealth of Massachusetts both placed historical markers along the route that Knox was believed to have taken.