Hello Fiona,
My maternal ancestry originates from two of the three parishes you have listed.
Margaret (née MacDiarmid) married Finlay MacDiarmid:
as follows -
Margaret MacDiarmid
b. abt. 1744-45
Marriage Date: 22 March 1760 Fortingall
Spouse: Finlay MacDiarmid
b. abt. 1740 Killin
Issue:
-John McDiarmid
b. 10 April 1761
-Duncan McDiarmid
b./Christened 13 February 1763
-Catherine McDiarmid
b. 26 April 1767
-*Jean McDiarmid
b. 02 April 1769
-Christian McDiarmid
b. 1772 Fortingall
-James McDiarmid
b. 17 April 1774 Fortingall
m. Mgt. LOTHIAN 1794, Fortingall
-Robert McDiarmid
b. 01 June 1777
Their 4th child was:
*Jean MacDiarmid
b. 02 April 1769
Marriage Date: 07 March 1790, Fortingall
Spouse: Peter Campbell
b. 1767 Dalchiorlich (sp?), Glenlyon
Jean (née MacDiarmid) and Peter Campbell's fifth child was:
Margaret Campbell
b./Christened: 22 February 1792 Dalchiorlich, Glen Lyon, Perthshire
d. 25 February 1870 Perth, Lanark County, Ontario, Canada
Marriage Date: 19 November 1815 Parish of Killin
Immigration Date: 1817
Spouse: Peter Campbell
b. January 1784 Rynachuilg, Loch Tay, Perthshire, Scotland
( 5 miles east of Killin)
d. 1848 Drummond Twp., Lanark County, Ontario, Canada
Margaret (née Campbell) and Peter Campbell were my gggGrandparents.
The spelling alternates between MacDiarmid and McDiarmid.
Kathleen