English and Scottish: from a Celtic personal name of great antiquity and obscurity. In England the personal name is now usually spelled Alan, the surname Allen; in Scotland the surname is more often Allan. Various suggestions have been put forward regarding its origin; the most plausible is that it originally meant ‘little rock’. Compare Gaelic ailín, diminutive of ail ‘rock’. The present-day frequency of the surname Allen in England and Ireland is partly accounted for by the popularity of the personal name among Breton followers of William the Conqueror, by whom it was imported first to Britain and then to Ireland. St. Alan(us) was a 5th-century bishop of Quimper, who was a cult figure in medieval Brittany. Another St. Al(l)an was a Cornish or Breton saint of the 6th century, to whom a church in Cornwall is dedicated.
FOREBEARS This name was brought to North America from different parts of the British Isles independently by many bearers in the 17th and 18th centuries. Prominent early bearers include Samuel Allen, who settled in Braintree, MA, about 1629 (died 1648 in Windsor, CT) and whose descendants included Ethan Allen (1737–89), leader of the Green Mountain Boys in VT during the Revolution; and William Allen (died 1725), from Dungannon, Ireland, an early Presbyterian settler in Philadelphia, whose descendants include William Allen (1803–79), governor of OH.
