The 4th New Jersey Infantry Regiment was an infantry regiment in the Union Army during the American Civil War.4th New Jersey Volunteer Infantry Regiment lost 5 officers and 156 enlisted men killed or mortally wounded and 2 officers and 103 enlisted men to disease during the Civil War. Col. J.H Simpson helps lead the 4th N.J through the hardship’s. Service Three months regiment The 4th New Jersey Infantry Regiment was first organized at Trenton, New Jersey for three months service on April 27, 1861. The regiment was attached to Runyon's New Jersey Brigade, Defenses of Washington, to June 1861. 1st Brigade, Runyon's Reserve Division, McDowell's Army of Northeast Virginia, to July 1861. Left New Jersey for Annapolis, Maryland, May 3. Reported to General Butler May 5, then moved to Washington, D.C., arriving there May 6. At Meridian Hill until May 24. Occupation of Arlington Heights, Va., May 24. Construction of Fort Runyon. Duty on line of Alexandria & Loudon Railroad until July 16. Advance on Manassas, Va., July 16-21. Battle of Bull Run July 21 (reserve). The 4th New Jersey Infantry mustered out of service July 31, 1861. Three years regiment The 4th New Jersey Infantry was reorganized at Camp Olden in Trenton for three years service on August 19, 1861 under the command of Colonel James H. Simpson. The regiment was attached to Kearney's Brigade, Division of the Potomac, to October 1861. Kearney's Brigade, Franklin's Division, Army of the Potomac, to March 1862. 1st Brigade, 1st Division, I Corps, Army of the Potomac, to April 1862. 1st Brigade, 1st Division, Department of the Rappahannock, to May 1862. 1st Brigade, 1st Division, VI Corps, Army of the Potomac and Army of the Shenandoah, to July 1865. The regiment was surrounded at Gaines Mill and most of its men taken prisoner. After the Seven Days Battles, they were freed by the Confederate authorities in a prisoner exchange. The 4th New Jersey had been armed with M1861 Springfield rifles, however upon returning from captivity, the authorities in Washington had no rifled muskets to rearm the regiment with, thus they were given outdated .69 smoothbore muskets. The regiment was forced to use them until the Battle of South Mountain in September, when they rearmed themselves with Enfield rifles dropped by retreating Confederates. Left New Jersey for Washington, D.C., August 20, 1861. Duty in the defenses of Washington, D. C., until March 1862. Advance