"The first Route 66 associations were founded in Arizona in 1987 and, in 1989, Missouri (incorporated in 1990)vand Illinois.vOther groups in the other US 66 states soon followed. In 1990, the state of Missouri declared US 66 in that state a "State Historic Route". The first "Historic Route 66" marker in Missouri was erected on Kearney Street at Glenstone Avenue in Springfield, Missouri (now replaced—the original sign has been placed at Route 66 State Park near Eureka). Other historic markers now line—at times sporadically—the entire 2,400-mile (3,900 km) length of road. In many communities, local groups have painted or stenciled the "66" and U.S. Route shield or outline directly onto the road surface, along with the state's name.This is common in areas where conventional signage for "Historic Route 66" is a target of repeated theft by souvenir hunters.
Delgadillo's Snow Cap Drive-In in Seligman, Arizona. The eatery is still a popular tourist stop.
Various sections of the road itself have been placed on the National Register of Historic Places. The Arroyo Seco Parkway in the Los Angeles Area and US 66 in New Mexico have been made into National Scenic Byways. Williams Historic Business District and Urban Route 66, Williams were added to the National Register of Historic Places in 1984 and 1989, respectively. In 2005, the State of Missouri made the road a state scenic byway from Illinois to Kansas. In the cities of Rancho Cucamonga, Rialto, and San Bernardino in California, there are US 66 signs erected along Foothill Boulevard, and also on Huntington Drive in the city of Arcadia. "Historic Route 66" signs may be found along the old route on Colorado Boulevard in Pasadena, and along Foothill Boulevard in San Dimas, La Verne, and Claremont, California. The city of Glendora, California, renamed Alosta Avenue, its section of US 66, by calling it "Route 66". Flagstaff, Arizona, renamed all but a few blocks of Santa Fe Avenue as "Route 66". Until 2017, when it was moved to the nearby Millennium Park, the annual June Chicago Blues Festival was held each year in Grant Park and included a "Route 66 Roadhouse" stage on Columbus Avenue, a few yards north of old US 66/Jackson Boulevard (both closed to traffic for the festival), and a block west of the route's former eastern terminus at US 41 Lake Shore Drive. Since 2001, Springfield, Illinois has annually held its "International Route 66 Mother Road Festival" in its downtown district surrounding the Old State Capitol.
Many preservation groups have tried to save and even landmark the old motels and neon signs along the road in some states.
In 1999, President Bill Clinton signed a National Route 66 Preservation Bill that provided for $10 million in matching fund grants for preserving and restoring the historic features along the route.
In 2008, the World Monuments Fund added US 66 to the World Monuments Watch as sites along the route such as gas stations, motels, cafés, trading posts and drive-in movie theaters are threatened by development in urban areas and by abandonment and decay in rural areas. The National Park Service developed a Route 66 Discover Our Shared Heritage Travel Itinerary describing over one hundred individual historic sites. As the popularity and mythical stature of US 66 has continued to grow, demands have begun to mount to improve signage, return US 66 to road atlases and revive its status as a continuous routing.
The U.S. Route 66 Recommissioning Initiative is a group that seeks to recertify US 66 as a US Highway along a combination of historic and modern alignments. The group's redesignation proposal does not enjoy universal support, as requirements that the route meet modern US Highway system specifications could force upgrades that compromise its historic integrity or require US 66 signage be moved to Interstate highways for some portions of the route.
In 2018, the AASHTO designated the first sections of U.S. Bicycle Route 66, part of the United States Bicycle Route System, in Kansas and Missouri.[
