What is the name of Frigg's hall in Asgard?

The name of Frigg’s hall in Asgard is Fensalir.

Fensalir is an Old Norse name usually translated as “Fen Halls,” “Marsh Halls,” or “Water Halls.” It is described as the dwelling of Frigg, the goddess associated with marriage, motherhood, prophecy, and foresight. The watery imagery distinguishes her home from better-known halls such as Odin’s Valhalla and Thor’s Bilskirnir.

Fensalir appears in the Poetic Edda poem Völuspá, where Frigg mourns the death of her son Baldr there. It is also mentioned in Snorri Sturluson’s Prose Edda. Scholars have debated whether the name should be understood as “Fen Halls” or possibly “Sea Halls,” and some have compared Fensalir with Sökkvabekkr, the watery hall associated with Sága.

A common mix-up is confusing Fensalir with Sessrúmnir, Freyja’s hall in Fólkvangr, or Valhalla, Odin’s hall for slain warriors. Fensalir belongs specifically to Frigg.