Like Arkansas, Louisiana had come under Union control by 1863. Also like Arkansas, not all Louisianans had been keen about secession. Louisiana had one major connection to the Union that all other southern states lacked: New Orleans. New Orleans was the largest city in the South and also its banking and trading center. The city controlled traffic on the Mississippi River and comprised the largest slave market in the nation. Each year, northern speculators sent thousands of shackled men, women, and children into the human trafficking nightmare that was the New Orleans slave market. The victims would be then sold to bidders throughout the Southern states to be put to work in the cane, rice, and cotton fields.
This economic connection to the North marked Louisiana politicians as particularly conservative. Throughout the state's history, Louisiana lawmakers opposed any radicalism (state's rights or human rights) that could hurt the market. Lincoln's election in 1860 changed that, however. Like the rest of the South, Louisiana cast a wary eye on the Republican party, which it considered radical and revolutionary. Though by no means unanimous — because secession was considered treasonous and anarchic — the Louisiana legislature endorsed secession in January, 1861.
In April 1862, the Union navy and army took New Orleans with very little trouble and the city was placed under martial law. By May of 1862, the state's capitol, Baton Rouge, came under Union control. Within a year, Grant's forces had taken Vicksburg, the famed Mississippi River port north of Natchez, and effectively cut the Confederacy in two. Creole (mixed race) soldiers, who had formed Louisiana home guards, quickly enlisted as Union soldiers.
Many Louisiana men volunteered or were drafted to fight east of the Mississippi River. When the Louisiana capitol and largest city came firmly under Union control and the state was set for the country's first Reconstruction Plan during the Civil War, western Louisiana descended into lawlessness. Guerrilla war tactics were not just used on Union troops, but also on citizens. Roving bands of criminal gangs terrorized defenseless women, farmers, and enslaved people, and fought both Confederate and Union forces.
With its fairly easy victories on the river —and the criminal troubles in the Louisiana hinterlands —the Union realized that its best strategy to get to Texas would continue to be water-based. Thus, Nathaniel Banks initiated the Red River Campaign. This plan would send the Union navy, commandeered by David Porter, up river to Shreveport, the Confederate capitol. There, Porter's navy and Banks's army would meet up with Steele's troops from the Camden campaign. Then, the large army would march into Jefferson, Texas.
Banks's troops captured Fort DeRussy in Avoyelles Parish in March of 1864, thus allowing for Porter's navy to drive up river to capture the Red River's largest southern port, Alexandria. Banks did not want Porter to just chug up river to Shreveport, however. He needed to defeat Richard Taylor's Confederate army that was guarding Shreveport on its western side. One of Taylor's defenses was building dams at Toneville, Bayou Pierre, to drain the water from the Red River to halt Porter's advancements, and stationing troops at the Grand Ecore by Natchitoches. Thus, unable for Porter to continue to Shreveport, Banks's troops and Porter's troops proceeded on foot, burning plantations and cotton crops with impunity. Apparently, a local farmer told Banks that the best road to take to Shreveport was the stagecoach route through Pleasant Hill - it's believed that this anonymous man didn't want Banks to pass, and possibly burn, his own farm. Along this road (today's LA 175), Banks' army engaged with Taylor's men outside of Mansfield and Pleasant Hill in early April, 1864. Despite heavy casualties, Taylor's army defeated the Union troops.
The Union army returned to Alexandria with Taylor's troops in hot pursuit. Banks decided to flee back to New Orleans with its flotilla, seasonal drought and Taylor's preventive river diversions built up river had kept the Red River shallow above the Alexandria rapids, which halted the Union's river progress. Joseph Bailey, a Union officer, proposed building several dams to raise water levels above the rapids. Three dams made of trees, logs, and stones, were quickly constructed. These dams allowed the ships to ride the rapids down river with enough force to propel them southward. Though the Union navy was met all along the river with shrapnel, gun fire, and whatever else the locals could throw at them, the Union troops ultimately made their way back to New Orleans. After the debacle, the Confederate army built forts Randolph and Buhlow at Pineville to counter further Union attacks, but the forts were not ever needed for that purpose again. Within less than year, even with the victory at Mansfield, the Confederacy capitulated at Appomattox Courthouse, Virginia.