Why did the battle of fort Wagner happen in Charleston?

The Battle of Fort Wagner occurred in Charleston, South Carolina, as part of the Union's campaign to capture the strategic port city, which was a vital center for Confederate supply lines. The fort itself was positioned on Morris Island, guarding the entrance to Charleston Harbor. The Union aimed to weaken Confederate defenses and disrupt their operations, while the Confederates sought to protect the city and maintain their control over this critical area. The battle, fought in July 1863, was notable for the significant involvement of African American troops, particularly the 54th Massachusetts Infantry Regiment.