A superb example of an exceptionally rare and important Revolutionary War battle plan, that showing the British capture of Philadelphia in 1777. "The best military map of the fortification on the Delaware River" (Nebenzahl).

For the British forces, the capture of the rebel capital of Philadelphia would be a considerable coup, with enormous propaganda value, especially as entrenched American forces outnumbered the British, five to one. "With this in mind, Lord Howe began operations against the city in August 1777. But the network of American fortifications on the Delaware below the city were a formidable barrier. Instead of attacking the city directly from the water, Howe took an inland route, and after the battles of Brandywine and Germantown, entered the city on September 26th.

"Now the seaward fortifications presented an even more serious problem. So long as they were held by the Americans, Howe's army in Philadelphia could not communicate or be supplied by sea. In late October, Howe initiated an ambitious campaign against the river forts. Batteries were constructed along the Delaware bank opposite Ft. Mifflin. On October 21, two thousand Hessian troops attacked Ft. Mercer on the Jersey bank with great losses. To complete the fiasco, two British warships ran aground and had to be abandoned. By November, the tide began to turn, and Ft. Mifflin was forced to surrender. Cornwallis then crossed the Delaware and with 5,000 men attacked Ft. Mercer, which was abandoned by the Americans on November 20th. Washington's scheme of starving the British out of Philadelphia collapsed with the capture of the river forts" (Taliaferro).

The map depicts these actions in extraordinary detail, showing the British and American fleets in the Delaware River, and their troops on the Pennsylvania and Jersey shores. The opposing forces are indicated by highlights in red ink, for the British, and Blue for the Americans. The inset of Fort Island, also includes the location of Fort Mifflin. The main map shows the American fortifications, and obstructions across the river, which protected the strategic Fort, that the British held siege to from early October 1777, until mid-November, thus allowing Washington's Army to regroup following losses at Brandywine.

Later issues were published in 1779 and 1785, exhibiting changes to the title, location of the opposing forces, and the inset of 'Fort Island'.