There was a major split on the value of assaulting Mobile Alabama or Texas. US President Lincoln sided with general in chief Henry Halleck in that he believed Texas was more important. Secretary of the Navy Welles and General Grant preferred an assault on Mobile. As an aside, Halleck and Welles were well known enemies of each other.
The union began its assault on Mobile, Alabama on August 4, 1863.
A little over 3 hours
Alabama seceded from the Union on January 11, 1861, but when Alabama seceded from the Union, the northeastern county of Winston seceded from Alabama. Alabama was expected to secede. It had a large slave population and their leaders saw secession as their best way to keep the status quo.
David Farragut
Mobile
Confederate Admiral Franklin Buchanan was charged with the defense of Mobile Alabama. After a struggle, Buchanan surrendered to Union Admiral Farragut on August 23, 1864.
Mobile, Alabama was one of the few Southern ports that the Union had not captured or sealed off by the Union's blockade. Blockade runners were consistently evading the West Gulf Blockading Squadron. It therefore became necessary for the Union fleet to capture the city and shut down the rouge Rebel port city.
The role of Mobile, Alabama was a significant role in the US Civil War. The city passed several resolutions even passed a resolution to succeed from the Union.
The capturing of Fort Henry is important, because it opened up a river highway into the heart of the south. Now, Union Gunboats could now travel on the river as far a northern Alabama.
One of them was the liberation of the port of Mobile, Alabama. Another was the final victory over Jubal Early in the Shenandoah by Phil Sheridan. Put together, these three Union victories restored Northern morale after months of depressing news, and revived Lincoln's chances of winning the November 1864 election.
Mobile, Alabama was not only an important port for foreign trade but was also used to build ships. It was the second most important port on the Rebel's Gulf coast. With that said, the thinking in Washington DC may have been that Mobile, a coastal city could be kept under control without a large expense of Union resources. The Mississippi River, however, was another story. The Union had no clue as to what the Confederates might be doing along that river. And, with New Orleans captured, it was wiser to allocate resources to take control of that river.
Admiral David Farragut was one of the USA's best admirals. If one were to narrow down his best two achievements in the US Civil War, one was certainly capturing New Orleans and seizing control of the valuable port of Mobile, Alabama.