Brig. Gen. John Pope, USA and Flag-Officer Andrew H. Foote, USN
Brig. Gens. John P. McCown and William W. Mackall, CSA
Pope had a large corps called the Army of the Mississippi, while the Confederate garrisons were much smaller.
Exact casualties are unknown.
After the surrender of Forts Henry and Donelson, Tennessee, and the evacuation of Columbus, Kentucky, P.G.T. Beauregard, commander of the Confederate Army of the Mississippi, had to revise his strategy for protecting the Mississippi River. The next natural strongpoint was Island No. 10, about 60 river miles below Columbus. There the river made a long loop, and batteries on the Island could fire on ships headed south, then again as they tried to move north around the bend. Just as important, the current would carry any disabled ship ashore where the Confederates could capture her. Nearby was New Madrid, on the Missouri shore, and a potential weak point. It also had heavy batteries to control the river, but they could also be turned to fire inland.
John Pope was the man tasked to open the upper Mississippi. He commanded the Army of the Mississippi, which he organized in St Louis before setting out on the long march through rough and swampy terrain on the west side of the river. On February 28 he started from Commerce, Missouri, to attack New Madrid, the first step in the campaign. They struggled overland through swamps, heaving supplies and artillery, and reached the New Madrid outskirts on March 3, beginning a siege.
Brig. Gen. John P. McCown, the garrison commander, defended both New Madrid and Island No. 10 from the fortifications. He had about 8,000 men in total, although active strength was usually lower thanks to fevers and camp diseases (including childhood diseases, since many of the farm boys had never been exposed to mumps or measles) the fighting strength was much lower. Island No. 10 had 19 heavy guns, New Madrid had 21, a Confederate gunboat flotilla had a mixed array of light and heavy guns, and the floating battery New Orleans, anchored below the Island. Yet there was a weak point: the supply route. Normally supplies could move by river, either all the way to New Madrid and Island No. 10, or at least up to Tiptonville and then by road up to the troops. But if the Tiptonville road was cut, the swampy terrain that protected the Confederate eastern flank would become a trap, with no way out for the garrison.
Pope’s army arrived outside New Madrid on March 3, and soon probed the defenses with the 4th Ohio, who were caught in a heavy crossfire and quickly retreated. Pope recognized the strength of the position and moved to outflank it; on March 6 Union troops overran the battery at Point Pleasant. This effectively closed the river as a supply line, making Tiptonville the key position. Meanwhile, Pope was bringing siege guns forward, and on March 13 he had them in place – only 300 yards from the Confederate outworks. That day saw a vicious artillery duel, with Confederate ships firing over the levee from the river (the water level was extremely high) and helping. But at the end of the day McCown saw the writing on the wall: Pope had a stronger supply line and sooner or later would pound the New Madrid defenses to bits. So he evacuated, hastily. The artillery and supplies of all kinds, even a prepared meal, were left behind when the river craft carried the men to the eastern shore.
Pope moved in on the 14th, but that was as far as he could get without naval support. Foote was convinced that the batteries at Island No. 10 were too strong to run, and that to duel them was also extremely risky. So he did two things. He brought up mortar boats to shell the fortifications, and he (in conjunction with the army’s engineers) explored and began to dig a canal through the neck of land north of Island No. 10. The mortar boats fired day and night (at night the burning fuses were picturesque) but did remarkably little damage; it looked like the canal would be more important. But the canal was a slow project, and even when completed wouldn’t be deep enough for ironclads, only shallow-draft transports.
For 15 days from March 20 the engineers dug and sawed trees. It was hot and heavy work, but successful: four transports and six light barges were hauled through the narrow canal. Pope began to convert the barges into gunboats, determined to get over the river himself if the navy wouldn’t help. And Foote was still strongly opposed, but Commander Henry Walke, of the Carondelet was bolder. He thought that under cover of darkness he could sneak past the batteries, especially since the river was very high and the current would help. Still, Walke took precautions like dousing all but one light, diverting the smokestack into the paddle-boxes, and lashing a barge onto the exposed side of the ship. It worked: on April 4, in the middle of a drenching thunderstorm the Confederate batteries got only two hits, and inflicted no casualties.
Three nights later the Pittsburg also ran the batteries, but the Carondelet had already ranged up and down the river, smashing Confederate batteries. With two powerful gunboats available, Pope used them to cover his crossing, and on the 7th he had strong forces across the river and had cut the Tiptonville road.
Brig. Gen. William W. Mackall, who had recently replaced McCown, knew there was no way out. Aside from a handful of men who picked their way through the swamps, the garrison – over 7,000 men - surrendered on April 8. The Mississippi was now open down to Fort Pillow, Tennessee. And Pope had a reputation that would take him into Virginia.