The Oldest Numbered Highways In The United States

Ask a driver in central Wisconsin what road they are on and the answer might be a number that a sign painter first stenciled onto a telephone pole in 1918. That spring, Wisconsin became the first place in the world to mark a whole network of highways with numbers instead of names, and several of those original figures still appear on the map today. Michigan followed with its own numbered trunklines soon after, and within a few years the idea had spread across the Upper Midwest and into New England. It reached the whole country in 1926, when the American Association of State Highway Officials approved a coordinated national grid on November 11 of that year. This is how the numbers on America's road signs came to be.

Wisconsin Creates America's First Numbered Highway System

Wisconsin was the first state to replace the confusing collection of named trails and painted symbols with a systematic network of numbered highways. The state legislature created the State Trunk Highway System in 1917, and the Wisconsin State Highway Commission assigned numbers to the network the following year. Counties began putting up the new signs on May 24, 1918.

Several of those original numbers remain on Wisconsin maps today. WIS 13 originally ran north through central Wisconsin toward Lake Superior, passing through the general corridor of Wisconsin Rapids, Marshfield, and Ashland. The modern highway has changed considerably, but it still travels through Marshfield and continues north through communities such as Phillips before reaching the Lake Superior shore.

WIS 19's original route was longer than the modern highway, but the early corridor between Sun Prairie and Watertown still carries the WIS 19 designation. Drivers following it today through communities including Marshall, Waterloo, and Watertown are therefore using a highway number introduced more than a century ago. In 1918, WIS 23 ran east from Packwaukee toward Sheboygan. That general east-west corridor still carries WIS 23 today, although reconstruction and bypasses have altered the physical roadway. Highway officials later extended the number west through Wisconsin Dells and Dodgeville, but the original eastern section kept the same designation.

Michigan Quickly Follows Wisconsin

Wisconsin's idea did not remain unique for long. Michigan became the second place in the world to both designate and post a systematic numbered highway network, with its first M-route signs going up in 1918 and 1919. Maps produced by the Michigan State Highway Department in 1919 already show the numbered trunkline system that became the ancestor of today's familiar M-highways.

Several designations from that early network survive. M-28 began as a relatively short Upper Peninsula route. Later extensions carried it across much of the peninsula, and today M-28 is one of northern Michigan's major east-west roads. The modern highway bears little physical resemblance to its 1919 predecessor in places, but the designation has remained part of the state's trunkline system.

M-35 has a more complicated history. Planners originally routed part of it through the rugged Huron Mountains between the Negaunee area and L'Anse, but the difficult central section was never completed as envisioned. The number survived on a modified route. Today's M-35 runs north from Menominee toward Negaunee. The original M-37 route connected Battle Creek and Grand Rapids before highway officials gradually extended the designation northward. Modern M-37 now continues through much of the Lower Peninsula to Old Mission Peninsula near Traverse City.

Numbered Highways Spread Beyond The First Two States

The two neighbors showed how much simpler numbered routes could make automobile travel. Instead of following named highways such as the Yellowstone Trail or searching for painted symbols on poles, motorists could follow one number until it intersected another.

Other states soon began developing their own systems. Minnesota voters approved a constitutional amendment in 1920 establishing 70 trunk highway routes, and work on the system began in 1921. Minnesota's statutory route numbers, however, do not always correspond with the numbers displayed to motorists. Iowa also began assigning numbers to its highways during the early 1920s, and the numbers appeared on maps before the state finished marking and remarking highways in the field in 1926.

New England Takes Highway Numbers Across State Lines

The next major step came in 1922. Until then, state highway numbers primarily helped travelers navigate within individual states. That April, the six New England states went further, agreeing on the New England road marking system to coordinate highway numbers across state boundaries. For a motorist, that was a significant improvement. A route no longer needed a different identity simply because it crossed a state line. The coordinated numbers ran through Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont, with one- and two-digit numbers for the major interstate routes and higher numbers for local roads.

The system lasted only a few years, but its coordinated numbers foreshadowed the national framework that arrived in 1926. Several of its corridors later became U.S. Routes, and New England Route 1, for example, turned into U.S. 1, even as most of the older numbers were replaced.

The U.S. Numbered Highway System Goes National

On November 11, 1926, the American Association of State Highway Officials approved the U.S. Numbered Highway System. For the first time, motorists had a coordinated nationwide route-numbering framework. Famous highways including U.S. 1, U.S. 11, and U.S. 66 belonged to this original network. As with Wisconsin's and Michigan's earlier state systems, planners generally laid the new numbers onto existing roads and travel corridors. U.S. 30 absorbed much of the Lincoln Highway corridor, and U.S. 40 took in portions of the historic National Road. U.S. 66 stitched together existing roads between Chicago and Los Angeles before a later extension carried it to Santa Monica.

The new numbers brought order to a landscape previously dominated by named auto trails. Odd numbers generally identified north-south routes, while even numbers indicated east-west highways. Major east-west routes commonly received numbers ending in zero. The familiar U.S. highway shield eventually became one of the most recognizable symbols of American travel.

The Numbers That Came First

America's numbered-highway story begins well before Route 66 or U.S. 1. Wisconsin marked the country's first systematic, publicly signed highway-numbering network in May 1918, and numbers including WIS 13, WIS 19, and WIS 23 remain in use today. Michigan followed almost immediately, and early designations including M-28, M-35, and M-37 are still on the map.

From there, the idea grew outward. Individual state networks became regional systems, and regional coordination ultimately gave way to the nationwide U.S. Route network in 1926. The roads themselves changed constantly, but the basic idea first tried in Wisconsin proved remarkably durable: give a road a simple number that motorists can follow.