The colonists first used this trail to deliver mail using post riders. The first ride to lay out the upper Post Road started in January 1, 1673. Later the newly blazed trail was widened and smoothed to the point horse-drawn wagons and stagecoaches could use the road, the country's first successful long-distance stagecoach service launched by Levi Pease along the upper road in Oct 1783.
During the 19th century, turnpike companies took over and improved pieces of the road. Large sections of the various routs are still called the Kings Highway and Boston Post Road. Much of the Post Roads are now US Route 1, US Route 5, and US Route 20.
Mileposts were measured from the intersection of Broadway and Wall St. in New York (one block west of Federal Hall) and from the old Boston city-line on Washington Street near present day Massachusetts turnpike.