The Dindsenchas of Irish mythology give the physical origins, and etymological source of several bodies of water – in these myth poems the sources of rivers and lakes is sometimes given as being from magical wells.
Connla's Well is one of a number of wells in the Irish "Celtic Otherworld". It is also termed "The Well of Wisdom", or "The Well of Knowledge", and is the mythical source of the River Shannon. The epithet Connla's Well is known from the Dindsenchas.
Another well is described in the dindsenchas about Boann, in the text as ("Secret Well") mythologically given as the origin of the River Boyne. This well has also been referred to as Nechtan's Well, or the Well of Segais.
Some writers conflate both Nechtan's and Connla's well, making it the source of both Shannon and Boyne.
Loch Garman's mythological origin is also given in the dindsenchas – in some translations or interpretations of the text the source of the water is given as the Well of Coelrind, though this has also been rendered as port of .., or even fountain of ...