Davison, Davis
Davison, Davis—In the districts about Dungannon, and in Co. Derry, McDaid and McDade have anglicised the name Davison and Davis, in Gaelic Mac Daibhéid. The name Davitt, Devitt. Devith, and McDavitt are other forms of McDaid and it probably seems the name is a branch of the Clan Davison of the North of Scotland. Phelim Reagh McDavitt was Sir Cahir O'Doherty's right hand man at the taking and burning of the "maiden" city of Derry, in 1608, and the families to whom Phelim Reagh belongs, were known by the nickname of "The Burn Derrys," and many families of this branch migrated later to Co. Mayo and it has been said that the family from whom Michael Davitt sprang was of the "Burn-Derry" families.
Alphabetical Index of Anglicised Surnames in Ireland
See also Woulfe’s Irish Names and Surnames
… and O'Hart's Irish Pedigrees