|The Portsmouth (Virginia) Artillery was originally organized in Portsmouth, Norfolk County.|
|April 20||Mustered into Confederate service for one year under the command of Captains Cary F. Grimes.|
|July||Assigned to Artillery Battalion, Department of Norfolk.|
|April 1||Reorganized and assigned to Mahone’s Brigade, Department of Norfolk.|
|April-July||Assigned to Mahone’s Brigade, Huger’s-R.H. Anderson’s Division, Army of Northern Virginia.|
Engaged USS Lockwood.
|June 25-July 1||
Seven Days Before Richmond
Battle of Malvern Hill
Engagement with U.S. Navy.
|July||Assigned to Artillery Battalion, R.H. Anderson’s Division, Longstreet’s Command, Army of Northern Virginia.|
The battery was commanded by Lieutenant John M. Thompson. Major Saunders was not yet on the field and Captain Cary F. Grimes commanded the battalion until he was mortally wounded at Piper’s farm. Lieutenant Thompson would be promoted to captain to date from Grimes’ wound.
The battery was equipped with two 12-pounder Dahlgren Boat Howitzers and one 10-pounder Parrott Rifle.
From the tablet for Saunder’s Artillery battery that was at one time (presently missing) on the Antietam battlefield:
Between 9 and 10 A.M. of the 17th, the four Batteries of this Battalion, under command of Captain Carey F. Grimes, went into position on this ridge in support of the Infantry engaged on the high ground northeast. Grimes’ (Virginia) Battery was on the immediate right of the pike, Moorman’s (Virginia) Battery, on Grimes’ right and between it and Piper’s Stone Barn, Huger’s (Virginia) Battery was immediately west of the pike, and Donaldsonville (Louisiana) Artillery (Maurin’s Battery) on Huger’s left, on the rising ground 140 to 170 yards northwest of this. The Battalion was subjected to heavy fire of Federal Artillery and musketry; Captain Grimes was mortally wounded about 60 yards east of this by a musket ball, many men and horses were killed and wounded, some of the guns were disabled and the Battalion was withdrawn toward Sharpsburg by Major John S. Saunders who was not present when it went into action.
Later in the day parts of the command assisted in checking the advance of the Ninth Corps on Sharpsburg.
|October 4||The Portsmouth Artillery was disbanded and its men ransferred to the Norfolk Artillery and the Lynchburg Beauregard Rifles. Captain Thompson went on to prison camp and staff duties.|