This corps was organized under General Orders No. 84, War Department, dated July 22, 1862, and was formed from the troops then under command of General John A. Dix at Fort Monroe, Norfolk, Portsmouth, Suffolk, and vicinity. Soon after its organization, its returns showed a strength of 9,574, "present for duty, equipped," with an aggregate of 11,738, "present and absent." In April, 1863, it comprised the divisions of Corcoran, Getty, and Gurney, including, also, two brigades which were stationed at Yorktown, under General Keyes, and one brigade at Norfolk, under General Viele; in all, 52 regiments of infantry, 9 batteries of light artillery, and 5 battalions of cavalry. The corps return for March 31, 1863, showed all aggregate of 32,741 present and absent, with 24,127 present for duty, equipped.
Corcoran's Division was in action, January 30, 1863, in an affair at Deserted House, Va., in which it lost 23 killed, 108 wounded, and 12 missing. Both Corcoran's and Getty's Divisions were engaged in the defense of Suffolk, losing 41 killed, 223 wounded, and 2 missing, the principal loss falling on Getty's Division.
In July, 1863, the brigade known as the Corcoran Legion was ordered on duty in the defenses of Washington; a part of the troops which had been engaged on the Peninsular march of June, 1863, were ordered to join the Army of the Potomac; other detachments were also made, after which the remaining troops were ordered transferred to the Eighteenth Corps, and the Seventh Corps was discontinued August 1st, 1863. On May 31, 1863, the Seventh Corps had attained a strength of 32,397 present for duty, with an aggregate, present and absent, of 43,648. Getty's Division was composed largely of veteran regiments which had served previously in the Ninth Corps.