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Ask the Rambler: What Is The Longest Road in the United States?

Welcome, once again, to the popular feature which allows the Rambler to make up a question he already knows the answer to, pretend he had to do a lot of eye-straining research, and submit a voucher for "travel expenses." Well, he's done it again, and we're not falling for it. But here's his answer anyway.


The longest road in the United States was once the second longest: U.S. 20 from Boston, Massachusetts, to Newport, Oregon.

This map of the Northwest shows the final routing of U.S. 20, U.S. 30, and other U.S. highways as approved by the American Association of State Highway Officials on November 11, 1926. Click for larger version 2 mb
This map of the Northwest shows the final routing of U.S. 20, U.S. 30, and other U.S. highways as approved by the American Association of State Highway Officials on November 11, 1926. Click for larger version 2 mb

When the State and Federal highway officials on the Joint Board on Interstate Highways conceived the U.S. numbered highway system in 1925, they decided that numbers ending in zero would be assigned to the transcontinental or major east-west routes, with the lowest number in the north (U.S. 2 was assigned to the northernmost route to avoid using U.S. 0). The transcontinental or major east-west routes were:

U.S. 2:  Houlton, Maine, to Bonners Ferry, Idaho.
U.S. 10: Detroit, Michigan, to Seattle, Washington.
U.S. 20: Boston, Massachusetts, to Astoria, Oregon.
U.S. 30: Atlantic City, New Jersey, to Salt Lake City, Utah.
U.S. 40: Wilmington, Delaware, to San Francisco, California.
U.S. 50: Annapolis, Maryland, to Wadsworth, Nevada.
U.S. 60: Chicago, Illinois, to Los Angeles, California.
U.S. 70: Morehead City, North Carolina, to Holbrook, Arizona.
U.S. 80: Savannah, Georgia, to Laredo, Texas.
U.S. 90: Jacksonville, Florida, to Van Horn, Texas.

The description of U.S. 20 in the Joint Board's report of October 30, 1925, read (all spellings as in the original):

From Boston, Massachusetts, to Springfield, Pittsfield, Albany, New York, Auburn, Batavia, Buffalo, Erie, Pennsylvania, Cleveland, Ohio, Maumee, South Bend, Indiana, Chicago, Illinois, Rockford, Dubuque, Iowa, Waterloo, Webster City, Sioux City, O'Neill, Nebraska, Chadron, Lusk, Wyoming, Casper, Shoshoni, Greybull, Yellowstone National Park, Idaho Falls, Idaho, Pocatello, Twin Falls, Boise, Payette, Pendleton, Oregon, Umatilla, The Dalles, Portland, Astoria.[Emphasis added]

The Secretary of Agriculture forwarded the Joint Board's report to the American Association of State Highway Officials (AASHO) for adoption. This transmittal reflected the fact that the States owned the roads. AASHO asked the States for their concurrence in the Joint Board's proposed plan and numbering.

A Numbering Switch

On December 30, 1925, Roy A. Klein, Secretary of the Oregon Highway Commission, wrote to William C. Markham, AASHO's Executive Secretary. Klein explained that the northwestern States supported the plan but had a number of concerns, including the routing of U.S. 20 and U.S. 30. On this matter, he said:

The Highway Commission of Oregon approves the numbering of the routes in Oregon with the exception of route #20. This route as at present shown on the map makes a long detour to the north through Yellowstone Park, thence south to Pocatello, Idaho and continues on to the Coast via the Columbia River Gateway. Many sections of this road are unimproved and the route is open only a few months in the year during the summer season on account of snow on the high altitude. Further, there is a $7.50 toll charge on entering the Park for all traffic. Because of this fact, Oregon recommends that Pocatello be made the western terminus of route #20, which is approved by Wyoming and Idaho.

The Highway Commission of Oregon favors the extension of route #30 through to the Pacific Coast via Ontario and the Columbia River, which would be effective west of Granger and extending through Kemmerer, Wyoming, Montpelier, Idaho, Pocatello, Boise, Ontario, Oregon, Pendleton, Astoria.

A conference was held at Detroit on this proposition at which were present James, Hewes, Purcell, Bureau of Public Roads; Peter and Blood, Utah; Sevison, Wyoming; Gregory, Idaho; Duby and Klein, Oregon.

At this meeting, Wyoming, Idaho and Oregon favored the designation of route #30 throughout as indicated above, the representatives of Utah, however, held out for route #30 through Ogden or Salt Lake. As finally agreed upon after considerable discussion, the section west of Granger through Kemmerer, Montpelier, Pocatello to junction point east of Burley takes the number 530 and the section through Evanston, Ogden (or Salt Lake), Brigham, thence via Snowville to junction east of Burley (present route #191) should take number 630, until such time as the section from Brigham through Snowville to the junction east of Burley be designated a part of the Federal-Aid system in both Idaho and Utah and improved to Federal-Aid standards, after which it would take the through route number 30.

Oregon's viewpoint was that the Columbia River Gateway was entitled to a through numbered route via Kemmerer between Granger and Burley for the reason that this route is an all year road direct to the whole Northwest; that for the greater part of the distance it has been improved to high standards, and that it is the best located topographically, as evidenced by the fact that it is the route traversed by the pioneers of the Old Oregon Trail and later by the Union Pacific Railroad. For that reason, the Oregon Highway Commission felt that the cutoff section should retain the through route number 30, rather than 530, a branch line designation; nevertheless, in view of harmony, its representatives agreed to the 530 designation.

As to the open question of the location of the route through Ogden or Salt Lake, Oregon's preference is for Ogden because this is a more direct route to the Pacific Ocean.

The adoption of the route #30 in lieu of #20 will necessitate a change in the numbering of 320 and 420, short branch line connections at Weiser and Umatilla, respectively. Would suggest #730 and #830 unless those numbers are assigned elsewhere.

Oregon is particularly interested in the designation of this route 30 in adjacent states as it is our only through route from the east and, until further improvements are made on the northern route through Montana, it is the best through route for the whole Northwest, hence our anxiety for a proper designation.

Markham replied on January 5, 1926:

The adjustments of Route 20 have already been agreed upon, and those changes together with others suggested by you will be put in form for submitting to the Executive Committee at their meeting in Chicago January 14-15, and you will be advised as promptly as possible of the action taken.

Thus, U.S. 20 was halted at the entrance to Yellowstone National Park, while U.S. 30 was extended to Oregon.

The Lincoln Highway Association Objects

The routing of U.S. 30 was of interest to the Lincoln Highway Association (LHA), backers of the era's most famous transcontinental route (New York City to San Francisco) and one of the first proposed, dating to September 1912. E. W. James, Chief of the Division of Design in the Bureau of Public Roads (BPR) and Secretary of the Joint Board, had approached the LHA to secure support for the plan to replace the country's many named highways. As James, who had conceived the numbering plan, recalled in a letter dated February 21, 1967:

Having assisted the Lincoln Highway Association in the First World War, I next went to Detroit to their headquarters and laid my scheme before them, very frankly telling them that it would mean the end of the Lincoln Highway Association, the Dixie, and all others. They understood it all; said they were for a big plan for roads across the U.S.; would be with my scheme if I would give the Lincoln Highway recognition so far as possible in the No. 30. I agreed to do all I could to put it across, and so had their support toward washing out all the named routes. They were the strongest of all the Associations and with them with us, who could be against us?

Following completion of the Joint Board's work, James contacted the LHA on October 26, 1925, to describe the outcome:

The route known as the Lincoln Highway is generally followed by United States Highway No. 30 from Philadelphia to Salt Lake City. Beyond Salt Lake City the Lincoln Highway is not followed by the Federal Aid System, but a considerable part of it is included in United States Highway No. 50 to Wadsworth, Nevada. From Wadsworth to San Francisco Route 40 covers the Lincoln Highway.

James was referring to the fact that under the Federal Highway Act of 1921, Federal-aid funds were restricted to a designated system that could not exceed 7 percent of the roads in each State, with 60 percent of the network required to be "interstate in character." Utah requested Federal-aid designation for the alignment of the Victory Highway (proposed in 1921 and sharing the Lincoln Highway's termini) into Nevada via Wendover. Because only one route into Nevada could quality for Federal-aid, Utah did not propose the Lincoln Highway routing in Nevada via Ely for Federal-aid designation.

The LHA protested vigorously, even to the point of a hearing on May 14, 1923, before Secretary of Agriculture Henry Wallace (the BPR was in the U.S. Department of Agriculture). The Secretary ruled on June 6 that under the law, he could act only on proposals by Utah's State highway agency, which favored Federal-aid status for the Victory Highway routing. When the Joint Board was designating U.S. routes, the Federal-aid designation and Utah's support gave the Victory Highway priority. It was assigned to U.S. 40, while the parallel Lincoln Highway was split among numbers as noted by James.

Nevertheless, James had delivered on his promise to the LHA that he would do what he could to assign as much of U.S. 30 to the Lincoln Highway as he could.

A few months later, the LHA was surprised to discover that U.S. 30 had developed a western extension to Oregon, far off the line of the Lincoln Highway. On April 3, 1926, Gael S. Hoag, the LHA's secretary, wrote to James about the change. Hoag had seen a new map of Oregon showing U.S. 30 where U.S. 20 had been and wanted to know why this scheme differed from the Joint Board's map. The letter did not explain Hoag's concern, but the Rambler speculates he may have hoped that "30" would someday be extended west on the Lincoln Highway, rather than diverted to the Northwest. On April 6, James replied:

Originally Route No. 30 stopped at Salt Lake where it converged with 40, which continued to the Pacific Coast. This convergence was made at the desire of Wyoming more particularly and created a condition which made it desirable to carry the route numbered 20 through Yellowstone Park down to Pocatello and thence west to Portland. A study of the geography of the Sierra Range will indicate to you that there was no other adequate method of developing the gateway at Ontario, Oregon.

This detail of the Joint Board was not satisfactory to the northwestern States, more particularly Oregon and Idaho, and when the situation was realized by Wyoming that State also was dissatisfied with the adjustments made, consequently the four States involved, namely, Oregon, Idaho, Wyoming, and Utah had a conference and agreed that the Ontario gateway should be developed by the only direct and logical route, for that purpose, namely, the route through southern Wyoming. This route as far as Granger was No. 30 from the Atlantic Seaboard, and in the readjustment this number 30 was carried on to Portland, number 20 being terminated at the Yellowstone Park.

All of the necessary adjustments of subnumbers [branches], etc., have been made and all of the States concerned in the adjustments have indicated their approval.

When AASHO members approved the U.S. numbered highway plan on November 11, 1926, the transcontinental and major east-west routes were:

U.S. 2:  Houlton, Maine, to Bonners Ferry, Idaho.
U.S. 10: Detroit, Michigan, to Seatle, Washington.
U.S. 20: Boston, Massachusetts, to Yellowstone National Park.
U.S. 30: Atlantic City, New Jersey, to Astoria, Oregon.
U.S. 40: Atlantic City, New Jersey, to San Francisco, California.
U.S. 50: Annapolis, Maryland, to Sacramento, California.
U.S. 60: Virginia Beach, Virginia, to Springfield, Missouri.
U.S. 70: Beaufort, North Carolina, to Holbrook, Arizona.
U.S. 80: Savannah, Georgia, to San Diego, California.
U.S. 90: Jacksonville, Florida, to Van Horn, Texas.

The log described U.S. 20 as follows (all spellings as in the original):

United States Highway No. 20.
Total Mileage, 2,542

Massachusetts Beginning at Boston via Worcester, Springfield, Lenox to the Massachusetts-New York State line west of Pittsfield.

New York Beginning at the Massachusetts-New York State line west of Pittsfield via Schodock Center, Rensselaer, Albany, Cherry Valley, Richfield Springs, Bridgewater, Cazenovia, LaFayette, Auburn, Geneva, Canandaigua, Avon, Geneseo, Warsaw, East Aurora, Athol Springs, Fredonia, Westfield to the New York-Pennsylvania State line west of Westfield.

Pennsylvania Beginning at the New York-Pennsylvania State line east of Northeast via Erie, West Springfield to the Pennsylvania-Ohio State line east of Conneaut.

Ohio Beginning at the Pennsylvania-Ohio State line east of Conneaut via Ashtabula, Geneva, Painesville, Cleveland, Elyria, Oberlin, Norwalk, Bellevue, Fremont, Woodville, Perrysburg Maumee, Charaghar, Oak Shade, Fayette, Alvordton, to the Ohio-Indiana State line west of Columbia.

Indiana Beginning at the Ohio-Indiana State line west of Columbia via Angola, LaGrange, Elkhart, South Bend, Michigan City, Gary to the Indiana-Illinois State line at Hammond.

Illinois Beginning at the Indiana-Illinois State line at Hammond via Chicago, Elgin, Marengo, Rockford, Freeport, Galena to the Illinois-Iowa State line at East Dubuque.

Iowa Beginning on the Illinois-Iowa State line at Dubuque via Manchester, Independence, Waterloo, Iowa Falls, Fort Dodge, Rockwell City, Early, Connectionville to the Nebraska State line at Sioux City.

Nebraska Beginning at the Iowa-Nebraska State line at South Sioux City via Laurel, Orchard, O'Neill, Ainsworth, Valentine, Rushville, Chadron to the Nebraska-Wyoming State line west of Harrison.

Wyoming Beginning at the Nebraska-Wyoming State line west of Harrison via Van Tassell, Lusk, Orin Junction, Douglas, Casper, Shoshoni, Worland, Greybull, Cody to the east entrance of Yellowstone National Park.

To The Northwest

By the late 1930's, Idaho and Oregon were thinking about an extension of U.S. 20 via newly improved roads. When AASHO's Executive Committee considered State routing proposals on June 21, 1937, it considered and deferred Oregon's request. The minutes of the meeting explained:

The continuation of a route from the Yellowstone Park to the Pacific Coast, suggested to be as follows:

"Beginning at the west end of the Yellowstone National Park; thence over U.S. 191 and U.S. 91 at Blackfoot; thence over Idaho State Route 27 to Arco; State Route 22 to Mt. Home; then coincident with U.S. 30 to Boise; thence State Route 24 to the Oregon State line."

"In Oregon it is proposed that the route shall coincide with U.S. 28 twelve miles to Vale; then over State Route 54 to Albany, via Juntura, Burns and Bend."

was not approved at the present time. The State Highway Department of Oregon reports that the proposed route will not be recommended for travel for two years. There are likewise parts of the route in Idaho not yet satisfactory. When the proposed route has been completed for satisfactory interstate travel, the Committee will again open the proposition.

Conditions had improved when the Executive Committee met on June 3, 1940. This time, the extension was approved:

Idaho-Oregon. U.S. 20 is extended west of the Yellowstone National Park to read as follows: Beginning at the west end of Yellowstone National Park, thence over U.S. 191 and U.S. 91 to Blackfoot, thence over Idaho State Route 27 to Arco, State Route 22 to Mount Home, thence coinciding with U.S. 30 to Boise, thence over State Route 44 to the Oregon State line. Oregon: Beginning at a point on present U.S. 30 north of Caldwell, Idaho, thence via Parma, Nyssa, Cairo Junction, Valle, Juntura, Burns, Bend, Tumalo, Sisters, Lebanon, to Albany.

With this extension, U.S. 20 was 3,277 miles long.

The Longest Road

U.S. 20 was now the second longest road in the country, behind U.S. 6. As the "6" designation suggests, U.S. 6 was not conceived as a transcontinental or major east-west route. The Joint Board had assigned the number to a route from Provincetown, Massachusetts, to Brewster, New York. By the time AASHO's member State highway agencies approved the numbering plan in November 1926, the route had been extended to Erie, Pennsylvania. Gradually, AASHO approved requests to extend U.S. 6 across the country. In 1937, it reached Long Beach, California, 3,652 miles from Provincetown. At this length, U.S. 6 was the longest road in the country. (For more information on the evolution of U.S. 6, see

That status lasted until June 18, 1963, when AASHO approved California's request to change the terminus to Bishop. This change shortened U.S. 6 to 3,227 miles as measured at the time. (According to the most recent U.S. numbered highway log, published in 1989 by the American Association of State Highway and Transportation Officials, the route is 3,249 miles long).

In 1963, therefore, U.S. 20 became the longest road in the country. U.S. 20 is 3,365 miles long according to the 1989 log. The route begins in Boston at a junction with Massachusetts Route 2 and ends in Newport, Oregon, at a junction with U.S. 101. Because U.S. numbered highways are not designated with National Parks, U.S. 20 is divided into an East Section ending at the eastern entrance to Yellowstone National Park and a West Section beginning at the west entrance to the park.

An Anomaly

The western extension of U.S. 20 to Newport, Oregon, created an anomaly in the U.S. highway numbering plan.

The Joint Board's 1925 version of U.S. 20 and U.S. 30 was consistent with the idea that the zero-numbers assigned to transcontinental and major east-west routes would increase from north (U.S. 2) to south (U.S. 90). The numbers on the West Coast were 10, 20, 40, and 60 in north-to-south order. When U.S. 20 was stopped at Yellowstone National Park and U.S. 30 extended to Astoria, Oregon, the numbering remained consistent with the plan (10, 30, 40, 50, and 80). Where U.S. 20 and U.S. 30 were parallel, "20" remained north of "30."

However, when AASHO approved extension of U.S. 20 to Newport, its placement violated the south-to-north pattern of zero-numbered routes because "20" ended up below "30." AASHO had little choice but to accept the anomaly because switching the western ends of U.S. Routes 20 and 30 for the sake of consistency was impractical. From a motorist's standpoint, such anomalies make little difference. Most motorists are not aware of the numbering plan conceived in 1925; they follow road signs and maps, so anomalies are not a source of confusion.