The national road was built with stone (crushed and solid), and it became one of the most expensive roads, if not the most expensive, in the United States in the early 1800s. For example, the privately funded Lancaster Turnpike, also built with stone, cost $7,500 per mile—versus $13,000 per mile for the national road.☜(ﾟヮﾟ☜) (⌐■_■)