Siege of Petersburg
The Richmond-Petersburg Campaign, commonly known as the Siege of Petersburg, was a series of military operations in Virginia that occurred towards the end of the American Civil War, ultimately spelling the end of the war for the Confederacy. The Siege of Petersburg includes the period the starts at the transfer of the Army of Potomac across the James River, the aftermath of the Battle of Cold Harbor and the evacuation of Richmond. This dates from mid-June, 1864 to April 1, 1865. The "siege" was far from an actual military siege in the traditional sense, but a full ten months of constant trench warfare consisting of General Ulysses Grant's unsuccessful attack on Petersburg and the construction of over 30 miles of trench lines around the city. With Confederate supply lines weakened, Grant launched a successful attack through the Confederate lines and captured the city, with the Confederates still buying enough time for General Robert E. Lee's army to escape. Lee would surrender eight days later to Grant at Appomattox Courthouse, Virginia on April 9, 1865.
The hellish trench warfare of the Petersburg Campaign would soon become a major part of warfare during the first World War.
The fortifications at Petersburg
Unofficially known as the "Dimmock Line", named for Captain Charles Dimmock, the outer line of the Confederate fortifications around Petersburg stretched for ten miles around the city from one side of the Appomattox River around to the other. 55 partially enclosed artillery batteries lined the fortifications, consecutively numbered from east to west, and linked together by trenches. Built on high ground, the fortifications included batteries and salients that projected out from the main defenses to deliver enfilade fire up and down the lines. Despite it's impressive size and strategic position, the "Dimmock Line" did have it's flaws. For example, between batteries 8 and 7 lay a deep ravine that provided an easy penetration opportunity for an attacking infantry force. Another example was the gap between Battery 24 and 25, also caused by a ravine. Insufficient fields of fire cleared for artillery as well too many of them exposed en barbette above the parapets provided the Confederates with yet another problem. To add to this matter, none of the Confederate batteries were fully enclosed, leaving them vulnerable to an attack from the rear.
Despite these fatal flaws General P.G.T. Beauregard stated that, if properly manned, the "Dimmock Line" was impregnable. This statement proved false when the Confederates were outnumbered seven-to-one and the line was broken on June 15, 1864. After the confederate withdrawal from the line, General Grant ordered the construction of a system of forts and breastworks circling the city.