This road, along with many side streets in Thornhill, is one of the oldest roads in Markham, with over 200 years of history. The road is believed to be built in the 19th century, named after John Colborne along with Colborne Street, immediately south of John Street. John Street was believed to be built around 1828-1836. Prior to that, Thornhill was a little community with houses along Yonge Street. John Street allowed eastward developments. The development of Thornhill in the 19th century stopped at what is now Henderson Avenue, and along the section of John Street between Yonge Street and Henderson Avenue are developments from that time. The area is now preserved under the city of Markham's Heritage Department. Along John Street in this area, the road signs are labelled as "Old Thornhill Circa 1794". This part of John Street is also considered as the heart of Old Thornhill.