Fort Washington ( Massachusetts ) Fort Washington is an historic site at 95 Waverly Street in Cambridge , Massachusetts . It was built by the Continental Army under the orders of George Washington in November 1775 . It is the oldest surviving fortification from the American Revolutionary War , built by American soldiers , and the only surviving fortification from the Siege of Boston . Fort Washington was placed on the List of Registered Historic Places in Massachusetts on April 3 , 1973 . History . American Revolution . In a letter to Joseph Reed dated Cambridge , November 27 , 1775 , George Washington wrote , " I have caused two three gun half moon batteries to be thrown up for occasional use . " The second three gun half moon battery was obliterated along with all other extensive siege works constructed by the British and Continental armies during the siege of Boston . These batteries and other minor works are shown on a map engraved by Henry Pelham , made for the British in 1775 and 1776 , and may well have been assumed by them to be of much greater importance than was actually the case . At the time these little fortifications were constructed , Henry Knox was on his way to Fort Ticonderoga to get the best of the cannons which were there and at Fort Crown Point . It was essential that the troops be trained in constructing works in which the guns could be mounted promptly when they were received . Post war . The property was acquired by the City of Cambridge and restored in 1857 , at which time three 18 pound cannons from the old Fort Warren ( located on Governor ' s Island ) were installed , and an elaborate granite and iron fence was designed by architect John R . Hall to protect the site . The best statement about the transfer to the city of the Fort Washington property seems to be that contained in the " Historic Guide to Cambridge " , compiled by members of Hannah Winthrop Chapter , DAR , in 1907 , on pages 179 - 180 . It is as follows : The three gun battery at the foot of Allston Street retains the semblance of a fort , and is called Fort Washington . The land where this battery was thrown up had been held in common from the close of the Revolution till 1857 , when it was deeded to the city by the following persons : Edmund T . and Elizabeth Hastings , Mary E . Dana , Joseph A . and Penelope Willard , John and Hannah B . Bartlett . A fund of $ 800 was also turned over to the city , by these people who cared for this plot of historic land . The conditions named include " that the above premises when suitably enclosed and adorned by said city , shall forever remain open for light , air , and adornment , for the convenience and accommodation of the owners of estates in said Pine Grove , and of the Public generally . " The city accepted this gift and with the assistance of the Commonwealth of Massachusetts proceeded to restore this battery to its original condition , to build a substantial fence around it and to erect a flag - staff . The Secretary of War gave three thirty - pounder guns ( Actually , Eighteen Pound American guns ) , and the Secretary of the Navy gave the gun carriages . The Massachusetts State Legislature voted to appropriate the sum of $ 2000 " provided the city of Cambridge shall appropriate a sum sufficient to complete the said fence at a cost of not less than four thousand dollars and said Fort Washington shall always be accessible to the public , and that said city shall always keep the fence proposed to in good repair . " The Cambridge city directory 1861 reported the Earthworks to be five years old in appearance and in excellent condition and the total cost of Fort Washington Park , was $ 9 , 504 . 05 . In 1965 the state passed legislation authorizing the city of Cambridge to transfer the park to the United States government as a historic landmark . However , the property remains a city park . Cannons . The guns standing in the embrasures are 18 - pounders and were cast during or shortly after the revolution . They are of very similar , if not the same cast as the two 18 - pounders at Stonington , Connecticut , that repulsed a British Invasion force on August 10 , 1814 . The two 18 - pound cannon at Stonington were cast in 1781 in Salisbury , Connecticut ( Stonington Historical Society , article - August 1982 , by Henry R . Palmer , Jr ) , during the Revolution . There are also two 18 - pound cannon at Mount Defiance in Ticonderoga , New York which are also from the Revolution and also of the similar cast . The three 18 - pounders were among those over - age cannon which were removed from the original Fort Warren , on Governor ' s Island , when a new Fort Warren was built on George ' s Island . Mr . Marcus Morton , of Cambridge , learned by correspondence with the Historical Section of the Chief of Ordnance in Washington , in 1942 , that the gun carriages were cast by the West Point Foundry on the Hudson River , and he discovered in the city records that it cost the city the sum of $ 13 . 50 to bring these guns from Governor ' s Island to Cambridge . These cannon are identical , except for the numbers and weights marked upon them . They are numbered 45 , 36 , and 40 ; and their weighs are shown as 30 - 0 - 13 , 30 - 0 - 17 , and 30 - 0 - 16 , respectively , ( in cwt . , qrs . , and lbs . ) . Those figures correspond to 3375 , 3377 , and 3376 pounds . The bore is approximately 5 5 / 8 inches ; the diameter of a 18 - pound sphere of cast iron is 5 . 1 inches ; the excess diameter of the bore ( called windage ) was usually about ¼ inch , or a little bit more , to allow for irregularities in the bore of the guns and the casting of the balls . The next larger standard size for cannon of that period was 24 lb . , which would require a bore of at least 5 . 9 inches . Image gallery . The following images are from the Library of Congress , Historic American Buildings Survey , Survey number HABS MA - 2 - 48 , MARCH 1934 : .