The inscription on the chart reads ‘Surveyed agreeably to the Orders and Instructions of the Right Honorable the Lords Commissioners for Trade and Plantations to Samuel Holland Esqr, His Majesty's Surveyor General of Lands for the North District of North America by Messrs Wheeler and Grant (Drawn by Jas. Grant 1775)’.  The map contains a very feint pencil note under the name Grant which notes that the map was drawn in 1775 and is signed in the bottom right by Grant (although much of the signature is now lost to wear and tear).

On this unique and previously unpublished map are shown the works constructed by His Majesty's troops and works thrown up by the 'Rebels'. It depicts the British troop positions in red and the positions of the American forces in yellow.  The subject content of the map dates between George Washington taking command of the American Army in July 1775 and before the American occupation of Dorchester Heights which finally forced an end to the conflict in March 1776.

Amongst the detail worth noting are the location of George Washington's head quarters at Cambridge from July 1775, General Lee's quarters to the North, and General Ward's quarters at Roxbury to the South.  It shows the fortification at the top of Breed's Hill as being in British hands (subsequently known as 'Bunker Hill' after the battle on June 17th 1775), as well as the point on Charlestown Peninsular where the British troops landed on that day under the command of General Howe.  Of no less significance is the inscription next to Great 'Bruster' (Brewster) Island in the entrance to the harbour which notes the destruction of the lighthouse situate there by the 'rebels' (300 American soldiers under Major Benjamin Tupper landed at the island on July 31 and burned the lighthouse down). 

The siege of Boston, although not the first engagement of the Revolutionary War, proved to be a galvanising experience for the American cause.  The American success was in no small part due to the ability of Washington who, although an inexperienced and often indecisive tactician and strategist, was an outstanding and motivational leader of men.