There are several articles written by various authors over the  years that explain the meaning of the Gillespie name, and its origins. There has been considerable controversy if the name with this spelling first appeared in Ireland or in Scotland, and in what location in each country. It seems to have evolved over time with different spellings from the 1100s, when the need arose to distinquish between many people with the same first name.

The Gillespie name appears consistently  in Northern Ireland records for over 300 years in Co Donegal to today, but the earliest record I have found so far in Ireland has been a military one in County Down for 1636. Genealogy records on the Internet cease in this period. Access to earlier manuscripts on parchment for the 1500s or earlier in university libraries  is severely restricted to the general public.

It appears that Gillespie families may have originally spread across Ireland from the north to south until the development of transportation made it easier to go in any direction by land. Many immigrants heading overseas throughout the history of the land left from the major ports of Derry, Belfast and Dublin, or Cork in the south. Many Irish  worked and lived  in Scotland during the 1800s, as seen in census records. The potato famine in Ireland during 1845-1849 thrust a million Irish out of Ireland, while another million died from starvation.

The distance between Ireland and Scotland at one time may have included a land bridge from Co Antrim, says historians. Today travel times between the two countries by boat or by plane is only an hour or two.

In Scotland the last name Gillespie is found mainly in records in Stirlingshire , and Kirkudbright in the 1600s. Other authors have stated the name was used in earlier centuries  but using variant spellings and without specific record found to prove that.

There were two migration schemes by  English kings to move Catholics off Northern Ireland estates during the 1600s, bringing Presbyterian Scots onto those properties from the main areas of Ayrshire and Stirlingshire. During that same upheaval a group of English settlers arrived in Londonderry, and remained in Derry, with others also sweeping down through the valleys into Co Fermanagh. No Gillespie has yet to be identified by name in records for that movement, but the research is not concluded. The influence of Scottish Gillespies from Northern Ireland (the Ulster Scot) is seen in many locations in North America.

Here are  links to websites are provided that specifically address this interest, and articles from other sources:

The Surnames of Scotland, Page 306

“This name is an attempt at the spelling of Gaelic Gilleasbuig, the ‘bishop’s gillie’ or ‘servant.‘    Ewan filus Gillaspeck witnessed a charter by the Earl of Levenaux c1175-99.  Between 1220-1240 Gillescop de Cletheueys witnessed a charter…the name had invaded Northumberland, appearing there as:  Gillaspik in 1364, Ghillaspie 1380, Gilaspy 1477, Gilhaspy 1508, Gillaspy 1528, Gillespey 1541,Gilhespy, Galeaspe 1653, Gilispie 1688.

Wikipedia – Gillespie

Website for Gillespie records world-wide