The end of this peninsula, as it would otherwise be, is converted into an island, of a mean length of about eight miles, by the Harlem River,--a narrow and partially navigable stream connecting the East and North rivers.
To the southern extreme of this island, called Manhattan, the city of New York was then confined.
As both the East and North rivers were navigable for large ships, the former throughout, the latter for over a hundred miles above its mouth, it was evident that control of the water must play a large part in warlike operations throughout the district described.

With the limited force at Washington's disposal, he had been unable to push the defences of the city as far to the front as was desirable.

The lower Bay was held by the British Navy, and Staten Island had been abandoned, necessarily, without resistance, thereby giving up the strong defensive position of the Narrows.

The lines were contracted thus to the immediate neighbourhood of New York itself.

Small detached works skirted the shores of Manhattan Island, and a line of redoubts extended across it, following the course of a small stream which then partly divided it, a mile from the southern end.