Why were Fort Fisher and Wilmington important throughout the war?

Wilmington was an important supply route for the Confederate Army, and Fort Fisher guarded it.
Wilmington was an important supply route for the Confederate Army, and Fort Fisher guarded it.

Wilmington was at an important rail junction that served many parts of the state, and Fort Fisher protected it.
Wilmington was at an important rail junction that served many parts of the state, and Fort Fisher protected it.

Wilmington became a goal for General Sherman to capture and burn, and Fort Fisher prevented that.
Wilmington became a goal for General Sherman to capture and burn, and Fort Fisher prevented that.

Wilmington became a destination for slaves to escape to, and Fort Fisher housed them.