Yonge Street was never the official name of a hamlet, village or town, but in the early days of York County it was an location sufficiently defined that it could be used on requests for grants of land (land petitions) made by would-be settlers.
Originally Yonge Street was planned as a road heading north out of the Town of York (now Toronto) destined for Lake Simcoe. The road was first surveyed in 1793 by John Graves Simcoe and a small group of soldiers. The following year the route began to be hacked out of the forest by soldiers and a group called the Berzcy settlers anxious to settle in the area, but first requiring some employment to keep them and their families housed and fed.
The sections of the road which were opened did not start at York and work northward. The area immediately around York was too swampy for a road to be laid without great expense. The first sections completed were much further north around the Berzcy Settlement at German Mills and around Thornhill. Once settlers were awarded their grants they were obliged to clear 33 feet of road in front of their lots and spend twelve days of each year on road maintenance (source:Wikipedia). Since most lots had a frontage of 0.05mi or 264ft it is not clear whether the 33ft of road clearance was an annual obiligation or whether the remaining road clearance was left to government contractors. Nevertheless, in the days before the invention of ashphalt and bulldozers, and given the damage caused by melting snows each spring, keeping the roads clear must have been a continuous and difficult endeavour.
Yonge Street continued to be of importance long after the original settlers. Up until the 1950s it was the principal road to the north and was often referred to as the "Longest Street in the World". It was also the dividing line between the townships of Markham and Vaughan, and between Whitchurch and King. In each village and town it went through (Lansing, Thornhill, Richmond Hill, Aurora, and the smaller places in between) it was the principal commercial street.