Based on the 1841 Scotland Census with the following Variants

McLAIN / McCLANE / McCLAIN / McLANE / MacLAINE
County - No. of Families/Heads of Households
Argyll - 21
Lanark - 101
Perth - 43
Inverness - 19
Aberdeen - 2
Midlothian - 16
Renfrew - 58
Berwick - 18
Aberdeen - 2
Angus - 17
Ayr - 48
Wigtown - 1
Dumfries - 3
Selkirk - 1
Stirling - 11
Dunbarton - 3
Kilcudbright - 17
East Lothian - 1
Banffshire - 4
Ross and Cromarty - 2

The original MacLAINE spelling was only numerous in Argyllshire, with 37 families close to the origin of the clan. The largest variant in this time period was McLANE, with 232 families