I was doing a paper on battles in the western theater of the Civil War and noticed that there were a lot more sources on Vicksburg than Port Hudson. Everything I read about Vicksburg said it was more significant because it allowed the Union control of the Mississippi River. Port Hudson out lasted Vicksburg so shouldn't Port Hudson be considered more significant?
Vicksburg was considered in U.S. Army Field Manual 100-5 to be the most brilliant operation ever conducted on U.S. soil; U.S. Grant cut himself off from his lines of communication, ran his gunboats through Vicksburg under fire, bluffed his landing site on the east bank of the river, then won a string of battles that left 30,000 Confederate soldiers cut off an invested in a siege and captured a Confederate state capital. The daring and skill of the campaign and the magnitude of the results make it much more prominent among historians of the operations.
Port Hudson usually gets treated as an aftershock of Vicksburg. There was no way for Port Hudson to hold out once Vicksburg fell, which is why its commander surrendered it shortly after the fall of Vicksburg. There were less than ten thousand men in Port Hudson, and with more than three to one besieging them, and more than ten to one in the Mississippi region, it was completely hopeless.
Moreover, the fall of Vicksburg coincided with Lee's defeat in Pennsylvania and the fourth of July; war in the Union camp was sustained by public morale, and that coincidence was absolutely electrifying to the public. It's prominence then gets reflected in the current historiography, perhaps out of proportion with its real significance. The Confederates had lost control of the river and their largest city when New Orleans fell, so it hadn't been much use to them, but Vicksburg had been one of the targets that Winfield Scott suggested in the early years of the war, so the feeling of having checked that off was a factor in the assessment.
Also crucial to the significance attached to Vicksburg relative to Port Hudson was that U.S. Grant was at the first but not the second. Grant was the most famous American in the world following the war, and was probably seen in person by more people than any American who ever lived following his speaking tour in Europe. This imparts great retrospective importance to everything he did prior, and Vicksburg was an obvious candidate for dozens, if not hundreds of books that have been authored since then.