Vandalia Citadel was one of the secret citadels established by the Heralds of the Mended Wood. It was known for its inhabitants who had suffered a great deal through their efforts to resist Morbin Blackhawk's evil regime.
The exact design of Vandalia's crest is unknown, but it is mentioned that it includes the colors blue and gold.
Vandalia Citadel is mentioned briefly, having sent a number of representatives to Cloud Mountain's Citadel Congress. When Prince Smalls' entourage sets out for Halfwind Citadel, it is said that they are headed for Vandalia Citadel. The advance party under Helmer includes Aubray of Vandalia, and both forces begin heading north to reinforce the deception.
Emma, newly named the heir to the throne of the Thirty Warrens, traveled with her company to Vandalia Citadel to seek refuge. While there, she met Lord Booker - who died shortly after her arrival - and his son, Lord Morgan. After some time, Emma left Vandalia to make for First Warren in order that she might confront her elder brother, Winslow.
- The map shown at the beginning of Ember Rising mistakenly spells "Vandalia" as "Wandalia".
- The name Vandalia is of uncertain meaning and origin, possibly being derived from either a Dutch or Native American group or the Germanic tribe known as the Vandals. At one point the area that is now the state of West Virginia was considered as the site of a fourteen British colony named Vandalia; the name has since been applied to a number of towns in the United States.