Recorded in many forms including McKeighan, McKeighen, McKeighan, as well as McCaghan, McCaughan, Mc Coughan, and possibly related to O'Keegan, McKeegan, and Keegan, this surname in the spellings above is from Ulster, Northern Ireland. It certainly lives up to the old Irish joke 'Its not what it looks like, - its what it sounds like that matters'. The research suggests that it originates as does Egan, Keegan and Hegan from the ancient 13th century MacAodhagain. This translates as 'The son of Hugh'. The surname seems to have originated in the counties of Tipperary, Kilkenny, and Offaly where name holders were known as lawyers and churchmen. It has been widely recorded in the north since the late 18th century, the earliest dates from which we have surviving church recordings. Certainly it is found now in every county in the province of Ulster. These early recordings include Robert McCaughan at Magheral, County Down, on September 10th 1790, and John Mc Keighan who married Margaret Christy on February 2nd 1869, at Balliniot, County Antrim. Possibly the earliest recording of the name in any form is that of Owen Mac Egan, the bishop designate of Ross, who was killed in battle in 1603 fighting the forces of Queen Elizabeth 1st of England. As it happens she who also died that year aged 70.