Way back when areas were first being "settled" by Europeans in the early 19th century, surveyors used something called a baseline road to measure out concession blocks. Yonge St was one of them, for example. The baseline road would be "cut" first and surveyed, then the concession blocks and associated concession roads for settlement would be surveyed out from there.
I'm only aware of a few baseline roads, but I know Hurontario and Yonge St are two.
What's also a little interesting tidbit of surveying history is why so many roads, especially east west roads in Toronto and York Region, have small jogs at intersecting concession roads. Basically surveyors in the early 19th century had pretty rudimentary tools, and were cutting through thick forests to measure out the original concession blocks. Every few concessions, they would "Check" their line, and adjust the concession to correct. The goal was to make sure every concession block was an exact size, in the case of York, about 2.1x2.1km. So you end up with jogs as the surveyors correct for their errors. it was quite a bit of complicated math to figure it out too, they had to do things like take into account the curvature of the earth, star positions, etc. All the while literally cutting lines through wilderness in harsh conditions.
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