On Sunday, June 21, 1931, the U.S. Department of Agriculture’s press office released a 14-page, typewritten announcement titled “U.S. Highway No. 66 from Chicago to West Coast is All-Year Route.” Its contents read like an enchanted road trip to exotic and far-off places (map included). Prairies, oil fields, high plateaus, relics of early settlements, deserts painted “in browns, yellows and tawny reds touched up with black and gray,” and a seemingly endless number of tourist attractions from Illinois to California are described. The announcement makes clear that this section of the United States that Route 66 cuts through is rich in history and industry and enough natural and man-made features that don’t have to work hard to prove Route 66’s case: it’s a road that should be traveled. Don’t miss out.

The press release confirms that Route 66 has never been considered just a road. It’s a conduit to which anyone in America could reach sights and places that had previously been inaccessible to them or difficult to get to by car. The sights and stops along the road, as well as the communities that grew up around it, made up the pot of gold travelers earn by driving parts or all of its 2,400 miles. (The National Trust’s Route 66 Roadies, for instance, have been captivated by the pride of small towns where the road cuts through and by volunteers committed to preserving Route 66 history, both the good and the bad.) But a story that rarely gets told is how Route 66 came to exist in the first place.

We might take our roads for granted now, expecting that (eventually) potholes will be filled in, congested roads will be widened, and road signs will be displayed clearly. But initially, roads were a “wild west,” a chancy form of travel that were often ducked in favor of railroads when possible. By the early 1900s, the country was marked by a disparate collection of roads, loosely bound by their meanderings from county to county and state to state, and which later bore names like "Pikes Peak Ocean to Ocean Highway" and the "Old Spanish Trail."

Some roads were wooden planks or just dirt paths created first by wagon ruts that were later leveled over. During heavy rains, cars got stuck in the squelching mud at places like the dreaded Jericho Gap in Texas. Other early roads were loose gravel or brick—a step up from dirt, but which still presented problems if not properly maintained. (The common asphalt surface we associate with highways and interstates didn’t come into popular use until after Route 66 became a federal highway. Most of the early Route 66, in fact, was concrete.)

Counties and states were casual in how they labeled their roads or alerted travelers to sharp turns or flood-prone valleys. A paragraph in a 1922 issue of Compressed Air Magazine notes a humorous 40-foot road sign in Tennessee that reads: “Drive Slow—Dangerous as the Devil.”

An early attempt to create, maintain, and manage roads gave rise to the "Good Roads" movement. Local farmers, businessmen, or county officials took it upon themselves to oversee roads that linked rural communities to the rest of the country—crucial farm-to-market roads.

“The start of the 'Good Roads' movement happened before the Model T was even built,” says James Powell, a Route 66 historian and founder of the Route 66 Association of Missouri. (In 1910, there were fewer than 500,000 registered automobiles in the country, but that number would spike in the next decade.)

In 1912, advocates of a transcontinental unified highway formed the National Old Trails Road Association and the Lincoln Highway Association. About 250 named trails were created in total, though they were still a hodgepodge of creative signage and various levels of paving success. These groups and others, like state motoring clubs, would provide long-distance travelers handy pamphlets explaining what they should pack in their car: spare tires, extra gasoline, a shovel and ax, flashlights, medical supplies, canned food, and a camera. Our confusion today over suggestions that sound like the items in a survival kit is warranted—were they going camping in some remote forest, or just taking a road trip?

In 1914, the American Association of State Highway and Transportation Officials (AASHTO) formed to encourage a road improvement program across the country. Soon after, early federal acts to provide funds for paving a small percentage of state roads were passed in the form of the 1916 Federal Aid Road Act and the 1921 Federal Aid Highway Act.

Finally, in 1924, increasing confusion over road names and frustration over road conditions lead to the formation of the Joint Board, made up of members from state highway departments and the Bureau of Public Roads (BPR), to determine a way to unify the thousands of miles of roads that tracked across the country. After dozens of meetings, plenty of disputes, and complicated questions with few clear answers, the Joint Board published a report in 1925 that detailed 145 numbered interstate highways totaling 75,884 miles.

Some people were suspicious of this state and federal government partnership, while members of the road associations expressed anger that they were essentially rendered obsolete. Others thought changing memorable road names like the Lincoln Highway to simplistic numbers was idiotic and unlikely to improve travel. But one of the biggest issues to come out of this was Route 60, known today as Route 66, which traveled in a backwards “C” from Chicago to L.A.

“Route 66 was an oddball,” Powell notes. “It wasn’t transcontinental, or north-south, or east-west.” Because it was a multiple of 10, Route 60 should have been assigned to a primary east-west transcontinental route, as established by the Joint Board. (Roads ending in "0" were considered primary, and thus the preferred roads to travel, while all other two-digit roads were secondary.) Kentucky, upset its east-west Route 62 was a secondary road that didn't link up with any primary routes, objected, wanting instead claim to Route 60. After weeks of discussions and meetings between Kentucky’s governor, AASHTO, and representatives of the BPR, they thought they had figured out a solution by changing Route 62 to Route 60. But not quite. Missouri and Oklahoma stepped in, upset that their primary Route 60 was taken away. More meetings, which took place over several months, finally resulted in the adoption on April 30, 1926, of U.S. 66, a number not previously assigned, that began in Chicago and ended in L.A. In November, the Secretary of Agriculture formerly commissioned the 2,448-mile-long Route 66. The United States Numbered Highways at this time had reached a substantial 96,626 miles.

Perhaps to entice travelers used to roads marked by potholes, fallen trees, and confusing signage, the 1931 press release pointed out that “practically the entire distance is an improved highway.” Nearly half of the road was hard-surfaced by then. Illinois, Kansas, and Missouri became the first three states to pave their sections of Route 66 by 1931 with concrete. The last unpaved section of Route 66 was celebrated in Oldham County, Texas, in 1938, one year before John Steinbeck released Grapes of Wrath.

The road itself was as diverse as the tourist attractions, diners, and towns along Route 66. Oklahoma’s “Ribbon Road,” for example, became part of Route 66 in 1926, but it was built several years before amid farmland as part of the Ozark Trail Highway. Measuring a skinny nine feet in width with a Topeka asphalt top, it’s the earliest surviving one-lane section of Route 66. In 1937 Route 66 was realigned away from Ribbon Road, and much of it was later paved over by state routes. It exists today as a reminder of the three eras of America’s road history: of named trails, of early numbered highways, and the current era of the four-lane interstate system.