The Irish sir name Coll may have several possible sources.Firstly ,The sir name is used for macColl, an Anglicized form of the gaelic mac Colla, Denoting the"son of coll'. This usage of the name is confined to County Donegal.

The Sir name Coll is infact of viking origin, Therefore ,The sir name Coll may have arrived in Ireland directly from Scandinavia, The Vikings having appeared off the coast of Ireland early as 
the year [795]..

In north Connacht the sir name may show Toponymic origin, Deriving from the old english word 'coll ' ,meaning a 'Hill'  or one who dwelt on a Hill.
About [1728] A William Coll from Kilmurray , Near Feenagh.
Acquired land in the townland of Clogher...And that was the beginning of the "coll Sir name"in and around 
South East, limerick!:-...