Recorded in several spellings including O' Calleran, Calleran, O' Colleran, Colleran, Calerane, Colerin, Colerine, and Colrein, this is an Irish surname. It has unproven or perhaps doubtful origins. It is apparently from County Galway and County Mayo, and by any standards is very rare only seventeen families being so recorded in any spelling in the 1865 county census, and hardly any more in more recent recordings. It would seem to have been recorded as O' Calleran at least as far back as 1602, although the actual origination is probably Norse-Viking pre 9th century. If this is correct the ancient spelling would have been 'Coll' which although used as a personal name actually means 'hill', and to this over the centuries has been added a diminutive suffix. This is usually '-ain' meaning 'little,' but more probably translates as 'son of'. It is also possible that the name is locational from the town of Coleraine in Ulster, but very few Irish surnames are locational so inspite of the spelling this is unlikely. Early examples of recordings include Teag O' Calleran in the rebels list of Ireland in 1601, Henry Calerane at St James Clerkenwell, in the city of London, on January 8th 1717, Nathaniel Colerin, who married Sarah Carter at St Dunstans in the East, Stepney, on July 7th 1724, and Bridget Colleran, at Lowpartk, County Mayo, on July 21st 1864.