Battery Wagner, the Assault of July 18, 1863
In early July, an amphibious federal force landed at Lighthouse Inlet at the Southern end of Morris Island and overran two thirds of the island before being stopped at Battery Wagner, a point which kept Federal guns just beyond range of Charleston, SC.
On July 18, 1863 General Quincy Gilmore threw an assault against Battery Wagner on Morris Island, which guarded the Southern approaches to Charleston Harbor. His goal was to capture the Battery and the remainder of the low, sandy, flea infested island (know locally as coffin island due to its use as a Lazzaretto and leper colony prior to the war). The fort was held by a small garrison of Confederate Infantry and Artillery and protected by a narrow approach up the beach, constricted by a marshy creek which funneled the soldiers onto a strip of sand a few hundred feet wide. After a heavy naval and land bombardment, as assault force led by the 54th. Massachusetts, an experimental black regiment of free men from the North went in with fixed bayonets to storm the fort. The bombardment had failed to destroy the sandbagged gun emplacements of the Fort and the assault column marched into a heavy artillery barrage and massed musketry. Much of the Fort's garrison consisted of troops from the Charleston area, including the Charleston Battalion. The 1st. S.C. Artillery was positioned on the right flank of the fort, in the sand dunes so as to sweep the front wall of the Fort with Canister. Fighting was fierce. The Federals were able to occupy a small portion of the fort and the 54th. planted its colors atop the parapet. After lengthy hand to hand fighting, the Federal troops were ordered to withdraw, leaving Wagner in Confederate hands. Losses were heavy.
Gen. Gilmore decided to attempt to take Wagner by siege, digging zig zag trenches towards the fort and moving his large guns to into ever closer range. The Navy also pounded Wagner from the sea, using a large calcium light at night to prevent to Confederates from rebuilding the fort. On some days a shell was thrown into Wagner every 30 seconds for hours at a time. The Fort held out another 58 days under heavy bombardment before being abandoned in September. During this period the shelling of Charleston began.

The July 18 Assault was featured in the movie Glory.
While portions of Morris Island still exist, most of the island eroded away after the war and the site of the Fort is today underwater. (The site of the Star of the West Battery/Battery Gregg on the North East end of the island has survived. The Swamp Angel Battery behind the island has been preserved.) The island's appearance now, however, is similar to that it had during the war, low, sandy and covered with scrub growth. Relics are occasionally found there.

Fort Wagner (also called Battery Wagner) was a fortification on Morris Island, South Carolina, that covered the southern approach to Charleston harbor. It was the site of two American Civil War battles in the campaign known as Operations Against the Defenses of Charleston in 1863.
The first engagement, the Battle of Fort Wagner or the First Assault on Morris Island, occurred on July 11, 1863. The second is better known. The Battle of Fort Wagner/Morris Island, was the Union attack on July 18, 1863, led by the 54th Massachusetts Volunteer Infantry, the first major American military unit made up of black soldiers. Colonel Robert Gould Shaw led the 54th Regiment on foot while they charged and was killed in the assault.
The Confederate fortifications, garrisoned by around 1,800 men, extended across the northern quarter of the low and sandy island. The main wall ran for 630 feet from the eastern ocean to salt marshes on the west. The wall was up to 30 feet high and a wide, but shallow, trench stretched in front. Much of the fort was earth barriers and sandbagged emplacements. The site of the fortifications is currently underwater.
The approach to the fort was constricted to a strip of beach 60 yards (55 m) wide. After a bombardment from both land and sea, the Union infantry moved in. The assault force was headed by the 54th Massachusetts and included five other brigades, around 5,000 men in total. Unfortunately for the assault force, the prior bombardment failed to seriously damage the fighting power of the fort. Consequently, the Union infantry suffered considerable casualties in the rush towards the fort.
As the Union troops reached the parapets, the fighting proved intense. Three brigades managed to occupy a portion of the walls, but they were forced to withdraw after an hour of fierce hand-to-hand combat where almost every officer was killed. The Union forces suffered around 1,600 casualties and the Confederate garrison under 200.
Although a tactical defeat, the battle proved to be a political victory for the Union since the valor of the 54th against hopeless odds proved the worth of black soldiers. It spurred additional recruitment that gave the Union Army a further numerical advantage in troops over the South.

The Union besieged the fort after the unsuccessful assault. After enduring almost 60 days of heavy shelling, the Confederates abandoned it on September 7, 1863.                 

The July 18 assault on the fort is dramatized in the Academy Award winning film, Glory.