The system of auto trails was an informal network of marked routes that existed in the United States and Canada in the early part of the 20th century.
Marked with colored bands on utility poles, the trails were intended to help travellers in the early days of the automobile.
Auto trails were usually marked and sometimes maintained by organizations of private individuals.
In the mid-to-late 1920s, the auto trails were essentially replaced with the United States Numbered Highway System.
The Canadian provinces had also begun implementing similar numbering schemes.