A 1993 phone-book count in Scotland revealed that of the 2,000 Gillespies and of the 4,000 Macphersons mentioned, the Gillespie geographic distribution gave a lower concentration in the Highlands than the Macpherson name, and a higher concentration in Argyllshire, Strathclyde, Perthshire and Fife. This area constitutes the ancient lands of Dal Riada and the Scottish dioceses of the ancient episcopal province of Armagh. The post clearances diaspora of Macphersons and Gillespies is therefore not the same, and the distribution in Scotland of the Gillespie name appears to confirm its ancient celtic origins, because, like the Kennedy name, it sits comfortably astride the water linking Belfast to Glasgow.
The "Scots Origins" website contains birth/marriage/death and census records between 1553 and 1926 for Scotland. In early 2002, the following number of Gillespie records existed on this site:-
OPRI and SRI Births and Christenings 1553-1901
10847
OPRI and SRI marriages 1553-1901
5477
SRI deaths 1855-1926
7254
1881 Census
3492
1891 Census
4148
1901 Census
4567
The more recent statistics were taken after Scottish emigration following the Clearances, although the low density of the name in the Scottish Highlands would indicate that the probable impact of the Clearances on those of the name was light.
It is intriguing to note that, in Northern Ireland, the Gillespie name is more associated with the Presbyterianism of Ulster than with the Catholicism of the Republic, to an extent that could lend credence to the idea of a purely Scots origin. If this were so, then the Gillespie families resident in the Province may well be themselves of Scots extraction, many of their ancestors having followed William of Orange's Scottish army into battle against his Catholic Stewart father-in-law, James II.