To make matters worse, at Allmusic.com, which is usually reliable (I should say, about as reliable as the record companies they get their information from) spells it DILLON BAY.

Folk-Legacy Records, which publishes Gordon Bok's album "Seal Djiril's Hymn," which contains the song, spells it DILLAN BAY on their web site.

I've been looking at several Gazetteers, and the only similar name I can find is Dillon Bay, which is part of Dillon Reservoir, adjacent to the town of Dillon, Colorado.