Texas was first

On March 9, 1985, the first-ever Adopt-a-Highway sign is erected on Texas’s Highway 69. The highway was adopted by the Tyler Civitan Club, which committed to picking up trash along a designated two-mile stretch of the road.

The Adopt-a-Highway program really began the year before, when James Evans, an engineer for the Texas Department of Transportation, noticed litter blowing out of the back of a pickup truck he was following in Tyler, Texas. Concerned about the increasing cost to the government of keeping roadways clean, Evans soon began asking community groups to volunteer to pick up trash along designated sections of local highways. Evans got no takers for his idea; however, Billy Black, the public information officer for the Tyler District of the Texas Department of Transportation, took up the cause and organized the first official Adopt-a-Highway program, which included training and equipment for volunteers. After the Tyler Civitan Club’s sign went up on March 9, other groups volunteered to beautify their own stretches of highway. The program eventually spread to the rest of the U.S. and to such countries as Canada, Japan and New Zealand.

[source: The History Channel]