Post road

A post road is a road designated for the transportation of postal mail. In past centuries, only major towns had a post house and the roads used by post riders or mail coaches to carry mail among them were particularly important ones or, due to the special attention given them, became so. In various centuries and countries, post road became more or less equivalent to main road, royal road, or highway. The 20th century spread of postal service blurred the distinction.

In what was to later become the United States, post roads developed as the primary method of communicating information across and between the colonies.

The Articles of Confederation authorized the national government to create post offices but not post roads. Adoption of the U.S. Constitution changed this, as Article I, Section Eight, known as the Postal Clause, specifically authorizes Congress the enumerated power "to establish post offices and post roads." This was generally interpreted liberally, to include all public highways. U.S. Supreme Court justice Joseph Story defended the broad interpretation that had become dominant in his influential Commentaries on the Constitution of the United States (1833).

Notable American post roads built for the purpose include:

Chemin du Roy was built between Montreal (Repentigny) and Quebec City from 1731 to 1737, for mail and as a means of travel for the key settlements in New France/Lower Canada. It was later incorporated as Quebec Route 2 and is now part of Quebec Route 138.

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