In his memoirs, Admiral David D. Porter recollected a November 1861 meeting with President Lincoln and navy secretary Gideon Welles in which—he says—he suggested the plan to seize New Orleans from the sea.
Lincoln liked the idea and added: “while we are about it, we can push on to Vicksburg and open the river all the way along.” Porter’s foster brother, Captain David G. Farragut, would command the expedition while then-Commander Porter led the assisting mortar-boat squadron.
January 20, 1862: Secretary Welles promoted Farragut to flag officer and command of the West Gulf Blockading Squadron. His first order was to “take possession of [New Orleans] under the guns of your squadron, and hoist the American flag thereon.” But that was not the only objective: “If the Mississippi expedition from Cairo shall not have descended the river, you will take advantage of the panic to push a strong force up the river to take all their defenses in the rear.”
From the base at Cairo, Illinois, the navy was assisting the army to assemble a squadron of ironclad and wooden river gunboats with supply and transport vessels to descend the Mississippi and split the Confederacy. In early February, under Flag Officer Andrew H. Foote, the Western Gunboat Flotilla facilitated Brig. Gen. U. S. Grant’s conquest of Forts Henry and Donelson, Tennessee. Foote then proceeded downriver to take Island No. 10 near New Madrid, Missouri, April 7, the second day of the battle of Shiloh.
April 24: Farragut blasted his big warships past Forts Jackson and St. Philip, brushed aside Rebel river forces, and secured the city; Maj. Gen. Benjamin Butler and 5,000 troops took possession on May 1.
After a few days repairing battle damage, the Gulf Squadron surged northward. Baton Rouge and Natchez—nearly defenseless—surrendered but powerful Vicksburg batteries absorbed concentrated bombardment and returned blistering fire. The flag officer assessed the fortress as unassailable from the river while water levels were falling, threatening to strand his deep-draft vessels.
May 16, Fox to Farragut: Assistant Secretary of the Navy, Gustavus V. Fox, read in New York papers that the squadron had retreated south rather than continuing upriver past Vicksburg to Memphis. He dispatched a letter in triplicate by the fastest three ships he could find: “This information may not be true,” the letter said, “but the probability of it has distressed the President.” But first, he telegraphed Farragut at New Orleans: “Carry out your instructions of January 20 about ascending the Mississippi River, as it is of the utmost importance.”
After the bloodbath and near disaster at Shiloh, Maj. Gen. Henry W. Halleck sidelined General Grant and was conducting a month-long, tedious siege of Corinth, Mississippi, where Gen. P. G. T. Beauregard holed up with his army.
Fox’s letter to Farragut continued: “So soon as we heard of the fall of New Orleans, we notified Foote and Halleck that you would be in Beauregard’s rear at once.” They had learned “with great pleasure” of his progress toward Vicksburg. But now, “this retreat may be a fatal step as regards our western movements.”
The Gulf Squadron’s presence at Memphis would flank Corinth, blockade the river, and force Beauregard to fight or retreat, besides capturing the enemy’s gunboats, “which have already made one attack upon our Western Flotilla, and are preparing for another.”
Meanwhile, Flag Officer Charles H. Davis had relived Foote and led the Western Gunboat Flotilla on downriver. At Plum Point above Memphis on May 10, Rebel gunboats rammed and sank two of his ironclads, although they were quickly raised and returned to service.
The Gulf Squadron’s initial ascent had caught Confederates by surprise, Fox continued, but now they were rapidly fortifying the river. “Still it is of paramount importance that you go up and clear the river with the utmost expedition. Mobile, Pensacola, and, in fact, the whole coast sinks into insignificance compared with this.”
Farragut’s complete execution of his orders would be, “the most glorious consummation in history.” Fox had hardly slept, he wrote, “especially as three weeks have passed and nothing except a return [to New Orleans] is rumored. . . . At any rate there is not a moment to be lost in the Mississippi.” 
May 19, Welles to Farragut: “SIR: The President of the United States requires you to use your utmost exertions (without a moment’s delay, and before any other naval operations shall be permitted to interfere) to open the river Mississippi and effect a junction with Flag-Officer Davis.”
Farragut struggled back upriver where Porter joined him with the mortar boats while Davis, on June 6, destroyed what was left of the Confederate river defense fleet at Memphis and continued toward Vicksburg with his gunboats, now redesignated the Mississippi River Squadron. Confederates abandoned Corinth on May 29.
June 28, Farragut to Davis: “We have been shelling [the city] with the mortar fleet two days and made the attack with the fleet proper this morning at 4 o’clock.” Vicksburg lay in the outside curve of a tight horseshoe bend with fortifications mounting 30 or 40 guns. As the warships steamed up channel straight at Rebel muzzles—not yet within the arc of fire of their own broadside guns—the enemy blasted away at unprotected bows, but took cover while the ships rounded the corner with sailors returning their best shots on the way by, and then opened up again on fragile sterns after the vessels passed.
Despite heavy fire in both directions, neither side inflicted much damage, one firing up at the bluffs while steaming and the other shooting down at moving targets on the river below with many rounds passing harmlessly over. Farragut’s flagship, USS Hartford, took several 50-pound rifle rounds and 8-inch solid shots to the hull; the nine ships lost four killed and thirteen wounded.
Farragut explained to Davis: the 3,000 soldiers with the Gulf Squadron could not land on the east bank against Maj. Gen. Earl Van Dorn’s division of some eight or ten thousand men ensconced there. And he would need to get back below the city soon to reconnect with their river supply line.
“I think, therefore, that so long as [Confederates] have the military force to hold the back country it will be impossible for me to reduce the place without your assistance and that of the army. . . . My orders are so peremptory that I must do all in my power to free the river of all impediments; that I must attack them, although I know it is useless, the river will soon be so low that we will not be able to get our ships down, so you see my position.”
June 28, Farragut to Welles: “SIR: I passed up the river this morning, but to no purpose. . . . I am satisfied that it is not possible for us to take Vicksburg without an army force of twelve or fifteen thousand men. . . . The water is too low for me to go over 12 or 15 miles above Vicksburg.”
June 28, Farragut to Halleck at Corinth: “SIR: I have the honor to inform you that I have passed the batteries and am now above Vicksburg with the greater part of my fleet. . . . My orders, general, are to clear the river. This I find impossible without your assistance. Can you aid me in this matter to carry out the peremptory order of the President? I am satisfied that you will act for the best advantage of our Government in this matter, and shall therefore await with great anxiety your reply.”
Flag Officer Davis and the River Squadron joined the Gulf Squadron on July 2. The largest U.S. Navy armada ever assembled on a river continued bombarding the city.
July 3, Halleck to Farragut from Corinth: “The scattered and weakened condition of my forces renders it impossible for me at the present to detach any troops to cooperate with you on Vicksburg. Probably I shall be able to do so as soon as I can get my troops more concentrated. This may delay the clearing of the river, but its accomplishment will be certain in a few weeks. Allow me to congratulate you on your great success.”
The general would explain to Secretary of War Stanton: “I can not at present give Commodore Farragut any aid against Vicksburg. I am sending reinforcements to General Curtis in Arkansas and to General Buell in Tennessee and Kentucky.”
July 10, Farragut to Welles: “SIR: It is not perhaps my province to take the liberty to say to the Department where my services may be most needed, but . . . under existing circumstances the services of my squadron would be much more essential to the interests of the country on the coast than in this river. Why?”
Because, he continued, the River Squadron had destroyed waterborne resistance and possesses sufficient naval force to keep the river clear. “I can do nothing here but blockade the port until the army arrives, which can be done as well by Flag-Officer Davis as by [us] both.” The city must be reduced by “the army getting in the rear” and holding it. “My services are required outside to look after my squadron from Pensacola to Brazos.”
July 14, Welles to Farragut: “SIR: The evacuation of Corinth has much lessened the importance of your continuing your operations on the Mississippi. The Army has failed to furnish the necessary troops for the capture of Vicksburg, and has not at present, it is represented, an available force to send there to cooperate with you in its capture.” He should return to the Gulf and operate, “at such point or points on the Southern coast as you may deem advisable, leaving Flag-Officer Davis in possession and control of the Mississippi as far down as may be expedient.”
“It was a fatal mistake,” recalled William T. Sherman in his memoirs, “that halted General Halleck at Corinth, and led him to disperse and scatter the best materials for a fighting army that, up to that date, had been assembled in the West.”
Secretary Welles groused to his diary in January 1863: “Had the army seconded Farragut and the Navy months ago, Vicksburg would have been in our possession. Halleck was good for nothing then, nor is he now.” Porter, Grant, and Sherman, would return to finish the job in July 1863.
 Admiral Porter, Incidents and Anecdotes of the Civil War (New York: D. Appleton and Company, 1885), 69.
 Welles to Farragut, January 20, 1862, in Official Records of the Union and Confederate Navies in the War of the Rebellion, 2 series, 29 vols. (Washington, D.C., 1894-1922), series 1, vol. 18, 7. Hereafter cited as ORN. All references are to Series 1, vol. 18.
 Fox to Farragut, May 16, 1862, ORN, 498-499.
 Welles to Farragut, May 19, 1862, ORN, 502.
 Farragut to Davis, June 28, 1862, ORN, 589.
 Farragut to Welles, June 28, 1862, ORN, 588.
 Farragut to Halleck, June 28, 1862, ORN, 590.
 Halleck to Farragut, July 3, 1862, ORN, 593.
 Halleck to Stanton, July 16, 1862, ORN, 636.
 Farragut to Welles, July 10, 1862, ORN , 675.
 Welles to Farragut, July 14, 1862, ORN, 595.
 William T. Sherman, Memoirs of Gen. William T. Sherman — Volume 1 (Kindle Edition) 179.
 Gideon Welles, Diary of Gideon Welles, Secretary of the Navy under Lincoln and Johnson, Howard K. Beale, ed., 3 vols. (New York, 1960), vol. 1, 218.