New Orleans in the American Civil War New Orleans , in Louisiana , was the largest city in the Southern States during the American Civil War . It provided thousands of troops for the Confederate States Army , as well as several leading officers and generals . Its location near the mouth of the Mississippi River made the city an important and early target of the Union Army , which occupied the city for much of the war , eliminating its vital status as a port for export of cotton and other Southern - produced trade goods . Early war years . The history of New Orleans is one of uninterrupted growth . In the 1850 census , New Orleans ranked as the 6th largest city in the United States , with a population reported as 168 , 675 . It was the only city in the South with over 100 , 000 people . By 1840 New Orleans had the largest slave market in the nation , which contributed greatly to its wealth . During the antebellum years , two - thirds of the more than one million slaves who moved from the Upper South in forced migration to the Deep South were taken in the slave trade . Estimates are that the slaves generated an ancillary economy valued at 13 . 5 percent of the price per person , generating tens of billions of dollars through the years . Antebellum New Orleans was the commercial heart of the Deep South , with cotton comprising fully half of the estimated $ 156 , 000 , 000 ( in 1857 dollars ) exports , followed by tobacco and sugar . Over half of all the cotton grown in the entire United States passed through the port of New Orleans ( 1 . 4 million bales ) , a full three times more than at the second leading port of Mobile , Alabama . The city also boasted a number of Federal buildings , including the New Orleans Mint ( a branch of the United States Mint ) and the U . S . Customs House . Louisiana voted to secede from the Union on January 22 , 1861 . On January 29 , the Secession Convention reconvened in New Orleans ( it had earlier met in Baton Rouge ) and passed an ordinance that allowed Federal employees to remain in their posts , but as employees of the state of Louisiana . In March , Louisiana accepted the constitution of the Confederate States of America . The Federal mint was seized and used to produce Confederate coinage , particularly half - dollars . Since the dies were not changed , these are indistinguishable from 1861 - O halves minted by the U . S . government . ( Using a different reverse die , only four " true " Confederate half dollars were ever made . ) New Orleans soon became a major source of troops , armament , and supplies to the Confederate States Army . Among the early responders to the call for troops was the " Washington Artillery , " a pre - war militia artillery company that later formed the nucleus of a battalion in the Army of Northern Virginia . In January 1862 , men from the free black community of New Orleans formed a regiment of Confederate soldiers called the Louisiana Native Guard . Although they were denied participation in fighting by Confederate policy , the Confederates used the Guard to defend various entrenchments around the city . Several area residents soon rose to prominence in the Confederate army , including P . G . T . Beauregard , Braxton Bragg , Albert G . Blanchard , and Harry T . Hays , who commanded the famed " Louisiana Tigers , " a brigade with a large contingent of Irishmen from New Orleans . New Orleans was initially a site of a CSA Naval Ordnance Depot . New Orleans shipfitters produced some innovative warships , including the " CSS Manassas " ( an early ironclad ) , as well as two submarine s ( the Bayou St . John Confederate Submarine and the " Pioneer " ) which did not see action before the fall of the city . The Confederate States Navy would also actively defend the lower reaches of the Mississippi at the Battle of the Head of Passes . Early in the Civil War , New Orleans became a prime target for the Union Army . The War Department soon planned a major attack to take back control of the city and its vital port , choking off a major source of income and supplies for the fledgling Confederacy . Fall of New Orleans . The political and commercial importance of New Orleans , as well as its strategic position , marked it out as the objective of a Union expedition soon after the opening of the Civil War . Captain David G . Farragut was selected by the Union government for the command of the West Gulf Blockading Squadron in January 1862 . The four heavy ships of his squadron ( none of them armored ) were , with many difficulties , brought up to the Gulf Coast and the lower Mississippi , and around them assembled nineteen smaller vessels ( mostly gunboats ) and a flotilla of twenty mortar boats under Commander David Dixon Porter . The main defenses of the Mississippi River consisted of two permanent forts , Fort Jackson and Fort St . Philip , as well as numerous smaller auxiliary fortifications . The two forts were of masonry and brick construction , armed with heavy rifled guns as well as smoothbores , and located on either riverbank so as to command long stretches of the river and the surrounding flats . In addition , the Confederates had some improvised ironclads and gunboats , large and small , but these were outnumbered and outgunned by the gathering Federal fleet . On April 16 , after elaborate reconnaissances , the Union fleet steamed up into position below the forts , and prepared for the Battle of Forts Jackson and St . Philip . On April 18 the mortar - boats opened fire . Their shells fell with great accuracy , and although one of the boats was sunk by counter - fire and two disabled , Fort Jackson was seriously damaged . But the defenses were by no means crippled , even after a second bombardment on the 19th . A formidable obstacle to the advance of the Union main fleet was a boom between the forts , designed to detain the ships under close fire should they attempt to run past . Gunboats were repeatedly sent up at night to endeavor to destroy the boom , but without much success . The Federal Navy bombardment of the forts continued , disabling only a few Confederate guns but keeping the gunners of Fort Jackson under cover and limiting their ability to respond . At last , on the night of April 23 , the gunboats " Pinola " and " Itasca " ran in and broke a gap in the boom . At 2 : 00 a . m . on April 24 , the fleet weighed anchor , Farragut in the corvette " Hartford " leading . After a severe conflict at close quarters , with the forts and with the ironclads and fire rafts of the defence , almost all the Union fleet ( except the mortar - boats ) forced its way past . The fleet soon steamed upriver past the Chalmette batteries , the final significant Confederate defensive works protecting New Orleans . At noon on April 25 , Farragut finally anchored in front of the prized city . Forts Jackson and St . Philip , isolated and continuously bombarded by the mortar - boats , surrendered on April 28 . Soon afterwards , the infantry portion of the combined arms expedition marched into New Orleans and occupied the city without any further resistance , resulting in the Capture of New Orleans . New Orleans had been captured by the Union without a battle in the city itself , and hence was spared the destruction suffered by many other cities of the American South . It retains a historical flavor with a wealth of 19th century structures far beyond the early colonial city boundaries of the French Quarter . New Orleans under the Union army . The Federal commander , Major General Benjamin Butler , soon subjected New Orleans to a rigorous martial law so tactlessly administered as greatly to intensify the hostility of South and North . Many of his acts gave great offense , such as the seizure of $ 800 , 000 that had been deposited in the office of the Dutch consul . Butler was nicknamed " The Beast , " or " Spoons Butler " ( the latter arising from silverware looted from local homes by some Union troops , though there was no evidence that Butler himself was personally involved in such thievery ) . Butler ordered the inscription " The Union Must and Shall Be Preserved " to be carved into the base of the celebrated equestrian statue of General Andrew Jackson , the hero of the Battle of New Orleans , in Jackson Square . Most notorious to city residents was Butler ' s General Order No . 28 of May 15 , issued after some provocation , that if any woman should insult or show contempt for any Federal officer or soldier , she shall be regarded and shall be held liable to be treated as a " woman of the town plying her avocation , " i . e . , a common prostitute . This order provoked storms of protests both in the North and the South , and also abroad , particularly in England and France . Among Butler ' s other controversial acts was the June hanging of William Mumford , a pro - Confederacy man who had torn down the U . S . flag over the New Orleans Mint , against Union orders . He also imprisoned a large number of uncooperative citizens . Butler ' s administration did have benefits to the city , which was kept both orderly and , due to his massive cleanup efforts , unusually healthy by 19th century standards . However , the international furor over Butler ' s acts helped fuel his removal from command of the Department of the Gulf on December 17 , 1862 . Maj . Gen . Nathaniel Prentice Banks later assumed command at New Orleans . Under Banks , relationships between the troops and citizens improved , but the scars left by Butler ' s regime lingered for decades . Federal troops continued to occupy the city well after the war through the early part of Reconstruction . New Orleans ' Civil War heritage . A number of significant structures and buildings associated with the Civil War still stand in New Orleans , and vestiges of the city ' s defenses are evident downriver , as well as upriver at Camp Parapet . On Camp Street , Memorial Hall ( founded in 1891 by war veterans ) boasts the second largest collection of Confederate military artifacts in the country .