出典:Wiktionary
The city in South Carolina was founded by German settlers, so the name in this case is probably of German origin. Compare with Valhalla.
This etymology is incomplete. You can help Wiktionary by elaborating on the origins of this term.
Walhalla
firebugs
ドクハキコブラ
ハジロオオシギ
waratahs
cornetfishes
douroucoulis
a shield