The Battle of Hatteras Inlet Batteries (August 28–29, 1861) was the first combined operation of the Union Army and Navy in the American Civil War, resulting in Union domination of the strategically important North Carolina Sounds.

Two forts on the Outer Banks, Fort Clark and Fort Hatteras, had been built by the Confederates to protect their commerce-raiding activity. These were lightly defended, however, and their artillery could not engage the bombarding fleet under Flag Officer Silas H. Stringham, commandant of the Atlantic Blockading Squadron, which had been ordered to keep moving, to avoid presenting a static target. Although held up by bad weather, the fleet was able to land troops under General Benjamin Butler, who took the surrender of Flag Officer Samuel Barron.

This battle represented the first application of the naval blockading strategy. The Union retained both forts, providing valuable access to the sounds, and commerce raiding was much reduced. The victory was welcomed by a demoralized Northern public after the humiliating First Battle of Bull Run. The engagement is sometimes known as the Battle of Forts Hatteras and Clark.

Hatteras Inlet in Confederate hands The North Carolina Sounds occupy most of the coast from Cape Lookout (North Carolina) to the Virginia border. With their eastern borders marked by the Outer Banks, they were almost ideally located for raiding Northern maritime commerce. Cape Hatteras, the easternmost point in the Confederacy, is within sight of the Gulf Stream, which moves at a speed of about at this latitude.Maury, The physical geography of the sea, p. 27. Ships in the Caribbean trade would reduce the time of their homeward journeys to New York, Philadelphia, or Boston by riding the stream to the north. Raiders, either privateers or state-owned vessels, could lie inside, protected from both the weather and from Yankee blockaders, until an undefended victim appeared. Watchers stationed at the Hatteras lighthouse would then signal a raider, which would dash out and make a capture, often being able to return the same day.

To protect the raiders from Federal reprisal, the state of North Carolina immediately after seceding from the Union established forts at the inlets, waterways that allowed entrance to and egress from the sounds. In 1861, only four inlets were deep enough for ocean-going vessels to pass: Beaufort, Ocracoke, Hatteras, and Oregon Inlets. Hatteras Inlet was the most important of these, so it was given two forts, named Fort Hatteras and Fort ClarkHenry T. Clark was Governor of North Carolina; see Trotter, Ironclads and Columbiads, p. 16. Fort Hatteras was sited adjacent to the inlet, on the sound side of Hatteras Island. Fort Clark was about half a mile (800 m) to the southeast, closer to the Atlantic Ocean. The forts were not very strong; Fort Hatteras had only ten guns mounted by the end of August, with another five guns in the fort but not mounted. Fort Clark had only five.ORA I, v. 4, p. 584. But see p. 591, where the number of mounted guns in Fort Hatteras is stated to be 12. Furthermore, most of the guns were rather light 32-pounders or smaller, of limited range and inadequate for coastal defense. The installations' water and powder supplies were also poor.

The personnel problem was even worse. North Carolina had raised and equipped 22 infantry regiments to serve in the war, but 16 of these had been drawn off for the campaigns in Virginia. The six regiments remaining were responsible for the defense of the entire North Carolina coastline. Only a fraction of one regiment, the 7th North Carolina Volunteers, occupied the two forts at Hatteras Inlet. The other forts were likewise only weakly held. Fewer than a thousand men garrisoned Forts Ocracoke, Hatteras, Clark, and Oregon. Reinforcements, if needed, would have to come from as far away as Beaufort.

Strangely, the military authorities in North Carolina did little to keep the poor state of their defenses secret. Several Yankee captains, victims of either capture or shipwreck, were loosely detained at or near Hatteras Island while awaiting return to their homes. They were allowed virtually free access to the forts, and made mental notes of everything. When they returned to the North, at least two of them gave full and valuable descriptions to the Navy Department.ORN I, v. 6, pp. 78–80.

Northern reaction The depredations on Northern commerce emanating from Hatteras Inlet could not pass unnoticed. Insurance underwriters pressured Union Secretary of the Navy Gideon Welles for remedy.ORN I, v. 6, pp. 77–78. Welles needed no prodding. He already had on his desk a report from the Blockade Strategy Board suggesting a way to perfect the blockade of the North Carolina coast. The board recommended that the coast be rendered useless to the South by sinking old, useless, ballast-laden ships in the inlets to block them.

Soon after he received the board's report, Secretary Welles began to implement its recommendation. He ordered Commander H. S. Stellwagen to go to the Chesapeake Bay to buy some suitable old hulks. At the same time, he was told to report his activities to Flag Officer Silas H. Stringham, commandant of the Atlantic Blockading Squadron. As such, he was the naval officer in charge of the blockade of the North Carolina coast. This was the first involvement of Stringham with what was to become the attack at Hatteras Inlet. In time, he would become the most important person in the expedition.

Stringham opposed the plan to block the inlets from the beginning. He believed that the tidal currents would either sweep the impediments away or would rapidly scour new channels. As he saw it, the Rebels could not be denied access to the sounds unless the inlets were actually held by the Union. In other words, in order to establish an effective blockade in this part of North Carolina, the forts that the state had set up would have to be captured. Since the Navy could not do it alone, the cooperation of the Army would be needed.

As it happened, the Army was willing to cooperate. Its willingness had something to do with the political general Benjamin F. Butler, who was a political force that had to be dealt with, but was already emerging as militarily incompetent. Butler was ordered to assemble a force of some 800 men for the expedition. He soon had 880: 500 from the German-speaking 20th New York Volunteers, 220 from the 9th New York Volunteers, 100 from the Union Coast Guard (an Army unit, actually the 99th New York Volunteers;ORA III, v. 1, p. 961.), and 20 army regulars from the 2nd U.S. Artillery.ORA I, v. 4, p. 581. The men were put aboard two of the vessels that Commander Stellwagen had purchased, and George Peabody. When objection was made that the two ships would not be able to survive a Hatteras storm, Stellwagen pointed out that the expedition could proceed only in fair weather anyway, as a storm would prevent landings.ORN I, v. 6, p.109.

While Butler was gathering his forces, Flag Officer Stringham was also making preparations. Somehow he learned that the War Department orders to Butler's superior, Major General John E. Wool, had contained the statement, "The expedition originated in the Navy Department, and is under its control."ORA I, v. 4, p. 580. Reasoning that he would be blamed if anything went wrong, he decided to follow his own plans. He selected seven warships for the expedition: , , , , , , and . All but the last were ships of the U.S. Navy; Harriet Lane was a revenue cutter, part of the US Revenue Cutter Service. He also included in his force the armed steam tug Fanny, needed to tow some of the surf boats that would be used for the landing.ORN I, v. 6, p. 120.

On August 26, the flotilla, less Susquehanna and Cumberland, departed Hampton Roads and moved down the coast to the vicinity of Cape Hatteras. On the way, they were joined by Cumberland. They swung around the Cape on 27 August and anchored near the inlet, in full view of the defenders there. Colonel William F. Martin of the 17th North Carolina Infantry, commanding at Forts Hatteras and Clark, knew that his 580 or so men would need help, so he called for reinforcements from Forts Ocracoke and Oregon. Unfortunately for him and his garrison, communication among the forts was slow, and the first reinforcements did not arrive until late the next day, when it was too late.

Opposing forces

Union Department of Virginia – MG. Benjamin F. Butler 9th New York Infantry Regiment – Col. Rush Hawkins (220 men) 20th New York Infantry Regiment – Col. Max Weber (500 men) 99th New York Volunteer Infantry Regiment ("Union Coast Guard") – Cpt. William Nixon (100 men) Detachment, 2nd US Artillery Regiment – Lt. Frank H. Larned (60 men) Detachments of sailors and marines from the fleet

Atlantic Blockading Squadron – Flag Officer Silas H. Stringham

Confederate 17th North Carolina Infantry Regiment, – Col. William F. Martin Fort Hatteras Garrison – Col. Andrews Unspecified naval volunteers, including Flag Officer Samuel Barron

Battle First day, to sunset Early on the morning of 28 August, , USS Wabash, and USS Cumberland began to bombard Fort Clark, while the lighter warships accompanied the transports to a point about to the east, where the troops began disembarking. Stringham kept his ships moving in a loop, with Wabash towing Cumberland. At 11:00 a.m., the USS Susquehanna—steaming towards Hampton Roads on a return voyage from the West Indies—happened upon the scene and was ordered to join the bombardment. The ships would deliver their broadsides against the fort, move back out of range to reload, and then come back in to fire again. By remaining in motion, they did not let the artillerymen in the fort correct their aim between shots, and thereby negated much of the traditional advantage of shore-based guns over those on ships. This tactic had been used previously by the British and French at the siege of Sevastopol in the Crimean War, but this was the first time it was used by the US Navy.ORN I, v. 6, p. 121.

The return fire from Fort Clark was ineffectual, either falling short or passing overhead, and no hits were made on the bombarding ships. Shortly after noon, the defenders ran low on ammunition, and about 12:25 p.m. they ran out completely. At this point, they abandoned the fort, some fleeing to Fort Hatteras, while others took to boats. Col. Max Weber, commanding the Federal troops already on shore, noted this and put some men in to take possession, but the fleet did not know this and continued firing for another five minutes. It was during this interval of confusion that the landing force suffered its only casualty, one of the soldiers being seriously wounded in the hand by a shell fragment. Fortunately, some of the troops were able to get the attention of the gunners on the ships by waving a large American flag, and the bombardment stopped with no further harm done.ORA I, v. 4, p. 589. Stringham and his captains then turned their attention to Fort Hatteras.

Meanwhile, the landings were not going well. Only about a third of the troops were ashore when rising winds produced surf that swamped and overturned the landing boats, and General Butler had to suspend further attempts to land. Colonel Weber found that he had only 318 men with him. The number included 102 from his own regiment, the 20th New York, but also 68 from the 9th New York, 28 from the Union Coast Guard, 45 artillerymen, 45 marines, and 28 sailors who could man heavy guns. With several field pieces that they had managed to wrestle ashore through the surf, they could reasonably well defend themselves against a Confederate counterattack, but they were too weak to mount an attack on Fort Hatteras.