Crawford Messenger: Salt and Mud: Early Roads and the First Turnpike in Western Pennsylvania
Pennsylvania Turnpike | highway, Pennsylvania, United States | Britannica
Turnpikes and Toll Bridges | The Encyclopedia of Oklahoma History and Culture
St Ives 100 Years Ago: Tolls and turnpikes
The Turnpike Roads
Kickapoo Turnpike opens for travel – Mustang Times
In US, what is the difference between highway, freeway, motorway, turnpike, causeway, parkway, expressway, etc.? Why are there so many names for the same thing? - Quora