Sketch map of the fortifications, rifle pits, plus Union and Confederate picket lines, outside Chattanooga, Tennessee, drawn by G.H. Blakeslee, US Topographical Engineers, in 1863. (Library of Congress)
Field fortifications also played an important role in Tennessee. Once Nashville fell after the capture of forts Henry and Donelson in February 1862, the Federal army wasted no time in fortifying that city. Included in these works were forts Morton, Casino, Gillem, and Negley (later renamed Fort Harker). Although never finished, the latter was the largest single fort west of the Washington defenses. Named for General James S. Negley, provost marshal and commander of Federal forces in Nashville, Fort Negley was built on St. Cloud Hill, and became the center of military operations in the Western theatre of the war.
Siege of Chattanooga, 1863
Following the disastrous Federal defeat at Chickamauga, the demoralized Rosecrans withdrew his army to the vital railroad center of Chattanooga, Tennessee, and threw up defensive works in preparation for a siege. Bragg arrived outside that city on September 23 and established a line of field fortifications that mainly extended along the western base of Missionary Ridge, and across the valley between Missionary Ridge and Lookout Mountain. From their lofty positions, the Confederates attempted to shell the city, but gave up after a couple of days because the range was too great to be effective and their fuzes were so poor.
Under the supervision of engineering specialist General Morton, the Federals worked constantly to strengthen their fortifications around Chattanooga before and during the siege. These works included forts Wood and Negley, which were linked together by infantry parapet. Outer works consisted of a line of rifle pits and a picket line. Following Grant's relief of Chattanooga on November 25, 1863, and while they were making the city the forward base of Sherman's drive on Atlanta, the Federals significantly altered these works. Inner strongpoints closer to the river to the east of the city included forts Sherman and Lytle; batteries
Fort Mouton (Redoubt B), Mobile, Alabama
By 1864, the city of Mobile, Alabama, was protected by 58 forts and redoubts with connecting breastworks. Construction of the middle line of defenses was supervised by Chief Engineer Lieutenant Colonel Victor Von Sheliha, of the Confederate Engineer Corps, and included Fort Mouton (Redoubt B), an isolated post situated on high ground behind Eight Mile Creek. Fort Mouton was a square redoubt with two bastions facing towards the outer defense lines.The inner works contained eight 8-inch columbiads, plus an unspecified number of 42-, 32-, and 24-pounder siege guns.The parapets of this fort were from 15-25 feet thick, and ditches through which tidewater flowed were about 20 feet deep and 30 feet wide.The garrison of Confederate troops also contained a large number of African-American laborers who were subject to the command of the engineers.
Bushnell, McAloon, Irwin, Taft, and Jones; plus Lunette O'Meara and Redoubt Putnam. Inner works to the west of the city included Fort Sheridan, on Cameron Hill, and forts Mihalotzy and Cameron, plus Battery Cooledge. Many of these works had blockhouse keeps, deep ditches, and steep scarps.
Siege of Knoxville, 1863
In early November 1863, Longstreet undertook his Knoxville expedition to divert Union troops from Chattanooga, and also to get away from Bragg, with whom he was engaged in a bitter feud. By mid-November, the city of Knoxville, held by forces under General Ambrose Burnside, fell under siege. On the 29th of that month a bastioned earthwork on a hill forming a sharp salient in the northeast corner of the entrenchments at Knoxville was assaulted. Named by the Federals as Fort Sanders, after cavalry General William P. Sanders who had been killed nearby 13 days earlier, the garrison of 250 men under Lieutenant S.L. Benbow was alerted as the Confederates attempted to assemble in the darkness to launch a surprise attack just before dawn. After some difficulty scrambling through wire entanglements, the assault force reached the ten-foot deep ditches on the north, west, and south faces of the fort with heavy loss. Without scaling ladders, few Confederates emerged on the scarp side, and only a small number entered the fort to be wounded, killed, or captured. Following their failure to take Knoxville, the Confederates withdrew and much of eastern Tennessee fell into Federal hands.
Drawn by John G. Orth, this map of Fort Sanders, Knoxville,Tennessee, illustrates the Confederate assault of November 29, 1863. Note the cannon firing, which shows the extent of the attack.The small "Rebel" flag flying on the northwest angle indicates the point at which the Confederates temporarily raised their banner on the Federal parapet with great loss of life. (Library of Congress)
Struggle for Atlanta, 1864
The Atlanta campaign lasted from July 1 to September 2, 1864. Following the Chattanooga campaign, Bragg retreated 25 miles south to Dalton, Georgia, and entrenched. However, Grant did not pursue him but instead went to Burnside's aid at Knoxville. As a result of public clamor, Bragg replaced Joseph E. Johnston in command during December 1864. Meanwhile, Grant was appointed General-in-Chief of the Armies of the US, and he proceeded east to Virginia, while General William Tecumseh Sherman was ordered to smash Johnston's army and "get into the interior of the enemy's country." In a series of thrusts, Sherman forced Johnston south towards Atlanta, a very important rail hub and industrial center for the Confederacy, and, after a victory at Kennesaw Mountain on June 27, 1864, closed in around that city.
According to the report of Captain Orlando M. Poe, Chief of Engineers under Sherman, the Confederate defenses at Atlanta "completely encircled the city at a distance of about one and a half miles from the center and consisted of a system of batteries open to the rear and connected by infantry parapet, with complete abatis, in some places in three and four rows, with rows of pointed stakes, and long lines of chevaux-de-frise. In many places rows of palisading were planted along the foot of the exterior slope of the infantry parapet with sufficient opening between the timbers to permit the infantry fire, if carefully delivered, to pass freely through, but not sufficient to permit a person to pass through, and having a height of twelve to fourteen feet. The ground in front of these palisades or stockades was always completely swept by the fire from the adjacent batteries, which enabled a very small force to hold them."
Rather than begin full-scale siege operations with saps and parallels, Sherman adopted the offensive tactic of creeping forward just before daylight each day, with each man hastily digging rifle pits that were subsequently linked together to form rifle trenches. These could be pushed forward to within 200 yards of any point on the Confederate lines with minimal loss of life. Towards the end of August, the Federal lines had been strengthened with batteries of 4%-inch guns, which maintained a steady fire upon the enemy's lines and upon the city of Atlanta. Thus, Sherman believed he could encourage the Confederate army, under command of General John Bell Hood since July 17, 1864, to either sally out and become involved in a general engagement, or evacuate the city. He eventually achieved both, and on September 1, following the failure of several sorties, the Confederate army burned and evacuated the city.
Siege of Savannah, 1864
Sherman's infamous "march to the sea" culminated in the siege of Savannah, which began on December 10, 1864. According to Lieutenant Colonel Charles Colcock Jones, Jr., chief of artillery for the military district of Georgia, the Confederate inner defenses at Savannah consisted of "detached works, located at prominent points, commanding the established avenues of approach to the city, crowning causeways and private crossings over these lowlands, and offering resistance wherever the swamps were practicable." Furthermore, canal banks were breached and river dams were cut, which contributed to the naturally flooded landward approaches to the city.
The 17th Iowa Infantry was guarding the railroad at Tilton, Georgia, in October 1864, when it was attacked by a Confederate force commanded by General Alexander P. Stewart. Lieutenant Colonel Samuel M.Archer, commanding the 17th Iowa, reported: "At 7 o'clock on the morning of the 13th my pickets on the railroad between Resaca and this place were fired upon ... they fell back to the blockhouse into which I at once placed as many men as could conveniently man the loopholes, and disposed of the rest in the pits on either side ... very soon we were surrounded by a very heavy force of skirmishers ... A brisk fire was maintained on both sides for four hours, during which time the rebels gained no ground,and were punished considerably ... They introduced three 24-pounder Napoleons, and opened a terrific fire upon us ... The roof was soon demolished and its timbers so much strained that the dirt covering rained down on us in torrents.The last and forty-seventh shot fired ... entered a loophole and exploded in the center of the room ... I surrendered the garrison, satisfied with having detained the rebels seven and a half hours." (Official Records, Vol. 39, Part I, pp 759-60. Photo: Library of Congress B81 I -2669)
A view of the interior of Fort McAllister, Savannah, taken after its capture by Federal forces on December 13, 1864.The large parados traverse standing in the foreground was designed to limit the area affected by explosions that might occur within gun positions during heavy and prolonged bombardment.The entrance work at bottom left also indicates that it probably served as a bomb-proof shelter or powder magazine. (Library of Congress B81 I -4004)
Fort Hardeman, Savannah
Fort Hardeman was situated in front of the extreme right of the Confederate line at Savannah. Planned and constructed under the immediate supervision of Lieutenant Colonel Bushrod W. Frobel, CS Engineers, this work enfiladed that part of the defenses, and consisted of a redan with an open gorge that rested on the Savannah River. Colonel Jones recorded that the "lunette, which constituted its prominent feature was approached by a covered way, and in it was located an ample bomb-proof made by cutting a deep ditch from the salient to the bastion line.This ditch was crossed at right angles by another of similar dimensions, commencing and terminating at the flank angles respectively.These ditches were then roofed with timber and covered with the earth removed in making the excavations.Thus was constructed not only a commodious bomb-proof, but also an excellent magazine. Semi-lunar in outline, the enclosed lunette constituted its center, with a redan on the left and a semicircular work on the right.The infantry line and curtains connecting these were substantial in character and showed a double front.The interior front commanded the terre-plein in case the enemy should attack from Hutchinson's island. Sand bags were used instead of headlogs, and they were so arranged as to permit the garrison, while firing, to be entirely under cover.The exterior front was protected by a double frieze of stakes and fence-rails planted firmly in the ground and interlaced with iron wire."
Designed by Captain John McCrady, Chief Engineer of the state of Georgia, the landward defenses consisted of forts Hardeman, Thunderbolt, Wimberly, Brown, Mercer, Boggs, Lee, Tattnall, and McAllister. The main batteries were named McBeth (railroad battery), Acee, Barnes, Pine-Point, Jones, Tucker's Point, Burnside, Green Island, Daniels, Harrison, Wilmington, Turner's Rock, Bonaventure, Hutchinson Island, and Causten's Bluff.
The most elaborate fortification in the Savannah defenses was Fort Hardeman, situated in front of the extreme right of the Confederate line (see box below). On December 9 and 10, the Federals attempted to capture this work, but the assaults were feeble and easily repulsed. It was a different story with Fort McAllister, a strong enclosed redoubt on the Ogeechee River to the south of Savannah. Defended by only a small garrison of 150 men, the big guns of this work were trained on the river, and not inland, and had already beaten off seven Federal naval attacks. Meanwhile, Hazen's division of the 15th Union Corps consisted of approximately 4,000 troops, which simply overran the defenses on December 13 and fought the Confederates hand-to-hand. Major George W. Anderson, Jr., commanding Fort McAllister, reported: "The fort was never surrendered, it was captured by overwhelming numbers." When artillery officer Captain Nicholas B. Clinch was called on to surrender during the assault, he responded with a thrust of his sword, and hand-to-hand combat continued, with Clinch going down only after having sustained three saber, six bayonet and two gunshot wounds. The capture of this fort sealed the fate of the city of Savannah, which was evacuated December 19-20, 1864.
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