[cf. Ir. erech, laden, burdened].
One of the eight sons of Míl Espáine in the Lebor Gabála[Book of Invasions]; in some versions Míl has only six sons, not including Erech and Erannán. When Erech appears it is only to accompany his brother Donn mac Míled in drowning during the invasion. His mother is Seang.