Camp of 2d N. H. Reg., Hill Top,
St. Charles County, Md., Oct. 28.

Since my last letter, the 2d Regiment have made considerable change in the locality of its camp. We are now encamped about 45 miles below Washington, near the Potomac, opposite the formidable line of rebel batteries extending from Mathias Point, several miles up the river. The division here is under the command of Gen. Hooker, now acting Major Gen., and comprises Sickles’ brigade and Hooker’s Brigade, (now under command of Col. Cowdin, of the Mass. 1st,) with a formidable force of cavalry and artillery. Our regiment occupies the left of the line. We have with us Doubledays’ battery of heavy guns, with the greater portion of the defenders of Fort Sumter. Our march here was a very interesting one, to us, and we will give your readers an account of it.