At night, marched 10 miles in the direction of Emmitsburg, and bivouacked at midnight near Marsh Creek. Early on the morning of the 6th, marched 1 mile, and bivouacked. Resumed march on the 7th through Creagerstown, and bivouacked 6 miles above Frederick City and 18 miles from bivouac of previous night. On the 8th, moved in heavy rain 12 miles across the Catoctin Mountains, and encamped near Middletown in the afternoon. On the morning of the 9th, the regiment crossed over South Mountain (a detachment of it assisting the train in its passage), and encamped near Boonsborough in the afternoon, 8 miles from Middletown. The regiment moved early on the day following, and in the vicinity of the enemy, on the Sharpsburg pike, near Jones Cross-Roads, was thrown forward to act as skirmishers. It was soon warmly engaged, and, after a severe and protracted skirmish, held the pike. The loss to the regiment was 2 killed and 6 wounded and missing. On the 11th, the regiment moved along the pike and westward, through field and wood, 2 miles, and bivouacked. On the morning of the 12th, advanced to the Williamsport road, and the next day crossed the Williamsport road and threw forward pickets. On the 14th, marched to Williamsport, and the morning following returned, marching through Keedysville, over South Mountain, and encamped near Burkittsville, having marched 20 miles. Moved forward on the 16th to vicinity of Berlin, where the regiment bivouacked until the afternoon of the 17th, when it crossed the Potomac, and marched 5 miles to Lovettsville. On the 18th, 19, and 20th, marched to Goose Creek, 30 miles from Lovettsville. Resumed march on the 22d, and bivouacked near Rectortown, 10 miles distant from Goose Creek. The regiment took part in the operations of the 23rd and 24th, in Manassas Gap, returning on the 25th, and encamped near Orleans, after a march of 20 miles. Resumed march in the morning, and on the 27th ultimo encamped 2 miles south of Warrenton.

Very respectfully, your obedient servant,

A. W. CLARK,

Captain, Commanding Twentieth Maine Volunteers.

Lieutenant JOHN M. CLARK,

Acting Assistant Adjutant-General, Third Brigade.

Numbers 198. Report of Lieutenant Colonel Norval E. Welch, Sixteenth Michigan Infantry.

NEAR EMMITSBURG, MD.,

July 6, 1863.

LIEUTENANT: In reply to circular of this date from brigade headquarters, as to the part this regiment sustained in the action of July 2 and 3, I have the honor to report: The regiment, under my command, lay with the Third Brigade,