Our branch of the Cathrae family left Scotland in the early 1840's. My great great grandfather was Martin Cathrae born around 1820 in County Roxburgh, Scotland. He is buried at Anaan, Ontario, near Owen Sound. His wife was Mary. They purchased land and farmed near Anaan. His son, John Cathrae was born in Scotland and was one of the first attendees at the first school at Leith, Ontario in the late 1850's.
In 1863 John bought (I am sure with his father's help) 100 acres of land near Bognor, Ontario and cleared it on weekends, walking back and forth from Anaan (20 miles). The farm was held in the family until 1973.
My grandfather was William Cathrae and my father is Ted Cathrae.
I don't know where you are from, but that is the story about this branch. Another branch came from Roxburgh Scotland around the same time, settling first in Newfoundland, then Nova Scotia, moving to Chicago and finally to Idaho.
That is a quick summary of our immediate family. I have most of the information about this branch of the family if you are interested.