Two Abraham Johnstons of Bruce County
Research note by Wesley Johnston, begun 4 Oct 2018, last updated 4 Oct 2018
https://www.ancestry.com/mediaui-viewer/tree/34820597/person/172045350124/media/3386e2f5-d06d-434f-86df-cf5f09d4113d
 
The Problem
Two different Abraham JOHNSTONs lived in Bruce County, Canada West (now Ontario) in the mid 1800's. At this point, no relationship is known between them.
The Carrick Township Abraham JOHNSTON
The elder of the two lived in Carrick Township, where the 1861 census ( https://www.ancestry.com/interactive/1570/4107386_00426?pid=794554259 ) lists him at age 30, with his wife Matlida and chidren Mary, Esalene and George.
The agricultural census of Carrick Township ( https://www.ancestry.com/interactive/1570/4391932_00641/789517192 ) shows him on lot 10 of Concession 12.
The Brant Township Abraham JOHNSTON
The younger one was single in 1861, but I am unable to locate him thus far in the 1861 census. He appears with his parents in the 1851/2 census ( https://www.ancestry.com/interactive/1061/e094-e002344401/131276 ) of Brant Township. But he does not appear with the family in the 1861 census ( https://www.ancestry.com/interactive/1570/4107386_00148?pid=794547623 ). But his 1865 marriage ( https://search.ancestry.com/cgi-bin/sse.dll?indiv=1&dbid=8510&h=71796&tid=34820597&pid=172031640936 ) shows him residing in Brant Township.