Errigal is the most southern, steepest and highest of the mountain chain, called the Seven Sisters. The Seven Sisters includes Muckish, Crocknalaragagh, Aghla Beg, Ardloughnabrackbaddy, Aghla More, Mackoght and Errigal. The nearest peak is Mackoght (from Irish: Mac Uchta, meaning son of the mountain-breast) which is also known as Little Errigal or Wee Errigal ().