A river, most probably the river in Cumbria, England.

According to a legend, Uther, a giant chieftain and founder of the Kingdom of Mallerstang, decided to build his castle in the Mallerstang Valley. To fortify his castle and protect it from potential invaders, Uther came up with the idea of creating a moat around it.

With his immense strength, Uther attempted to alter the course of the River Eden, intending to surround his castle with a large moat. However, despite his efforts, Uther struggled to control the powerful river, which resisted his attempts to divert its flow. Despite his failure to create the desired moat, Uther continued to rule over his kingdom in Mallerstang as a powerful giant chieftain.

It’s not certain, but Uther the Giant may be the same as Uther Pendragon.

Eden is derived from the Old English ēadn, meaning “pleasant” or “delightful.”