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British Spy Map of Lexington and Concord: A Detective Story

Today’s guest post is from Ed Redmond, a Cartographic Reference Specialist and Vault Collections Curator in the Geography & Map Division.

In school, we all learned about Paul Revere and his famous April 18, 1775 ride through the Massachusetts countryside warning of an impending British armed force marching from Boston, MA to the small towns of Lexington and Concord. But, of course, there is much more to the story, including the British commander of all troops in North America, British spies, patriotic tavern keepers, an unsigned manuscript map, and a Boston publisher.

Tensions between the colonies and England reached a boiling point in December 1773 with the Boston Tea Party when a group of colonists dumped tea from England into Boston Harbor. As a result, the British Parliament passed a series of laws that, among other things, installed British General Thomas Gage, as the governor of the Colony of Massachusetts in May 1774. By the winter of 1774-1775, however, in the face of continued rebellious activities, General Gage argued for an 18th century troop “surge” – as many as 20,000 additional troops – to pacify the countryside.

Several years ago, I stumbled across an unsigned manuscript map with the supplied title of “Roxbury to Concord. Roads & distances, &c.” This unique map was acquired by the Library of Congress in 1867 as a part of the Peter Force Collection, which includes more than 750 Revolutionary era printed and manuscript maps transferred to the Geography and Map Division.

At first glance, the unassuming map appears to simply depict the roads from Roxbury to Concord but, when paired with another primary source from the Library’s collections, a larger untold story of British spies skulking about the Lexington and Concord countryside emerges.

Title page from " General Gage's Instructions." 1779. Library of Congress.

Title page from General Gage’s Instructions. 1779. Library of Congress.

According to General Gage’s Instructions printed by Boston publisher J. Gill in 1779, General Thomas Gage, the commander of all British troops in North America at the time, ordered two British soldiers, Captain Brown and Ensign De Berniere, to discretely survey the roads in the vicinity of Boston.

“We set out from Boston on Thursday night, disguised like Gentlemen in brown clothes and reddish handkerchiefs round our necks; at the ferry of Charlestown we met a sentry of the 52nd regiment but Capt. Brown’s servant, whom we took along with us, bid him not to take any notice of us so that we passed unknown to Charlestown. From that we went to Cambridge, a pretty town with a college built of brick. We next went to Watertown and were not suspected. A little out of this town we went into a tavern, a Mr. Brewer’s, a whig, [and] we called for dinner…”

All of the towns mentioned in the text, including “Brewers” tavern, appear on the manuscript map. The two British “surveyors” then sent their various large scale surveys back to Boston with their servant and returned separately to avoid being discovered as spies.

"Roxbury to Concord. Roads & distances, &c." 1775. Library of Congress, Geography & Map Division.

Roxbury to Concord. Roads & distances, &c. 1775. Library of Congress, Geography & Map Division.

A few weeks later, on March 20, 1775, roughly one month before the events of April 18-19, 1775, Captain Brown and Ensign De Berniere received additional instructions from General Gage to survey the road to Concord:

“ We went through Roxbury and Brookline, and came into the main road between the thirteen and four-teen mile-stones in the township of Weston ; we went through part of the pass at the eleven mile-stone, took the Concord road, which is seven miles from the mainroad. The town of Concord lies between hills that command it entirely ; there is a river runs through it, with two bridges over it.

In addition to describing the roads and topographical features, our two spies were able to gather specific information on the artillery and provisions in Concord:

“We were informed that they had fourteen pieces of cannon (ten iron and four brass)… their iron cannon they kept in a house in town, their brass they had concealed in some place behind the town, in a wood. They had also a store of flour, fish, salt and rice ; and a magazine of pow-der and cartridges….”

Following their reconnaissance of Concord and vicinity the spies continued on to Lexington:

“We dined at the house of a Mr. Bliss, a friend to government ; [who] told us he could shew us another road, called the Lexington road. We set out and crossed the bridge in the town. The road continued very open and good for six miles, the next five a little inclosed, (there is one very bad place in this five miles) the road good to Lexington. You then come to Menotomy, Cambridge, and so to Charlestown…” .

Once again, all of the towns mentioned in the text (with the exception of Lexington) appear on our map. Additionally, the distances between the towns are laid down on the map and correlate with the figures given in the text, even though the map is not drawn completely to scale.

Detail from Roxbury to Concord. Roads & distances, &c.

Detail from Roxbury to Concord. Roads & distances, &c.

The last part of Ensign De Berniere’s Narrative describes the events of April 18-19, 1775, the British march from Boston to Concord via Lexington and subsequent return. Due to his local knowledge gained as a “surveyor”, De Berniere was selected to guide the expedition.

So what does all this tell us? To tie it all together, we have an unsigned manuscript map, a 1775 text written by a British officer which was captured when the British evacuated Boston and published in 1779, and, a more complete understanding of events leading up to the April 19, 1775 Battles of Lexington and Concord.


  1. susan morris
    April 18, 2016 at 10:21 pm

    Very interesting!

  2. Tony Carp
    May 11, 2016 at 1:28 am

    Very interesting, but in 1775 it was still a Crown colony, so the British Army weren’t spying on anyone, they were carry out a routine reconnaissance of potential insurgent capabilities and positions.
    Today we would use a drone.

  3. Dr. Herbert Misigo
    June 15, 2016 at 6:01 am

    A very good article to read.

  4. Michael Allard
    November 16, 2017 at 8:40 am

    Tony, reconnaissance is another word for spying!

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