John G. Barnard to W. H. Chesebrough, April 15, 1863

GENERAL:

I herewith send you the sketch of the south side of the Potomac* (with forts, batteries, rifle-pits, &c.), alluded to in my letter of the 31st ultimo.

In reference to the Defenses of Washington, it should be borne in mind that under this head are included many things not strictly connected with the defense of Washington itself.

For example, it is necessary to hold Alexandria, and this quite independently of the defense of Washington. This extends our lines over

Again the position of two great public establishments, viz, the navyyard anc arsenal, on the Eastern Branch, compels us to hold the crest of the chain of heights, 6 miles long, south of the Eastern Branch. Were it not for these establishments, we might abandon these heights

and make the Eastern Branch itself our defensive line, simply constructing a few batteries along its northern bank, from Fort Lincoln down to the navy-yard.

These matters should be understood as explanatory of the very large force it requires for the Defenses of Washington to resist a powerful attack.

very respectfully, your most obedient,