The Citadel most commonly refers to The Citadel, The Military College of South Carolina, located in Charleston, South Carolina, USA. It sits on a campus along the Ashley River and is known for its senior military college tradition and distinctive Moorish-inspired architecture. If you meant a different “citadel” (e.g., a ship’s protective structure or a fictional/Cultural reference), please specify the context and I’ll tailor the details. Context highlights:

• The Citadel, South Carolina: public senior military college in Charleston, founded in 1842, moved to its current Ashley River campus in 1922, enrollment around a few thousand cadets [The Citadel overview contextual details].
• If you were asking about a ship’s citadel: in maritime terms, the citadel is the armored area of a vessel protecting critical spaces and crew, typically located low in the hull or near the centerline, depending on ship design [general maritime concept].

If you can share the exact context (university, location, ship, or fictional work), I’ll provide precise coordinates, history, and current details.