Henry Knox was a Boston bookseller. Stocking books primarily of military history. He witnessed the Boston Massacre, helped develop fortifications around the city and directed cannon fire at the Battle of Bunker Hill.
In the winter of 1775-76, the city of Boston was blockaded by the King's Army (Red Coats). General Washington, who was impressed with his military skills had befriended Knox. In order to gain control history suggests that Knox told Washington of a plan to gain cannons and artillery from Ft. Ticonderoga and Crown Point, NY. Washington, appointed Knox to be in charge of this expedition and set out reaching Fort Ticonderoga on December 5, 1775.
The expedition back carried over 60 tons of cannons and artillery. Knox followed many paths, some prominent others to avoid detection by any of the King's Army down the Hudson River.
He entered Massachusetts on January 10 in Alford. By January 14 he had reached the path in Russell and continued on what was the Boston Post Road, and now Route 20. The original road veered at Palmer to enter Warren, Brookfield, Worcester to Shrewsbury. (See 1926 Route 20 map http://www.historicus20.com/uploads/3/4/4/1/34413072/route20_ma.pdf ).
On January 22, he entered Northborough. At this time, the Post Road was becoming increasingly monitored, so the many locals who were aware of Knox arriving, took him on various side paths to avoid detection. On the 25 he went through Sudbury, Wayland and Weston, the 26th Waltham, Watertown. And on January 27 - arrived in Cambridge.
A major military advantage came when the cannons arrived to Washington, fortifying Dorchester Heights, and on March 17 - the King's Army evacuated Boston.
Knox's plan is still considered one of the greatest actions in the Revolution.
In 1926 - the 150th Anniversary of this trek, markers were placed along the Route and updated in 1975, when the Bicentennial of the Knox expedition was researched heavily. From December through January 1975-76, a reenactment of Knox's trek was happened along the original route.
Today, most towns have a General Knox Trail marker prominently featured in a town square. While driving Route 20 in Massachusetts, you will see these. (Note- along original 1926 Route 20) The Knox Trail does veer off on MA Route 23 in Russell.