Hindarsfjall is one of the islands in the Skellige archipelago. There, one can find the sacred grove Hindar and Temple of Freya which is tended by the priestess Sigrdrifa. When Ciri goes missing Yennefer and Crach visit the island to speak with the priestesses of the Temple of Freya.
The Witcher 3: Wild Hunt
Ciri teleports to the island and is treated at a home in one of the island's villages, and afterwards briefly visits the local sauna before leaving. Upon leaving however the Wild Hunt attack the village. Ciri manages to flee the village on horseback with the help of Skjall.
Sometime later Yennefer and Geralt visit this village whilst searching for Ciri learning that she was there and in the presence of Skjall, whom had since one to sacred gardens to fight Morvarg and died. Geralt finds Skjall's body and Yennefer performs necromancy on it to discover information about Ciri, but ultimately killing the energy from the garden. For this the priestesses command that no one on Skellige is permitted to feed, shelter ot help Yennefer.