U.S. Route 10A (US 10A) was an alternate route of US 10 that existed between 1941 and 1967. From 1941 to 1947, it ran between

Seattle, Washington Seattle ( ) is the List of municipalities in Washington, most populous city in the U.S. state of Washington (state), Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the List of Unit ...

, and

Missoula, Montana Missoula ( ) is a city in and the county seat of Missoula County, Montana, United States. It is located along the Clark Fork River near its confluence with the Bitterroot and Blackfoot rivers in western Montana and at the convergence of five ...

. Since its decommissioning, it has been replaced by

Idaho State Highway 200 State Highway 200 (SH-200) is an east–west state highway in northern Idaho, United States. It travels along the north side of Lake Pend Oreille and the Clark Fork River between the Sandpoint area and the Montana border, where it continues a ...

(SH-200),

Montana Highway 200 Montana Highway 200 (MT 200) in the U.S. state of Montana is a route running east–west, across the entire state of Montana. From the starting point at Idaho State Highway 200, ID 200, near Heron, Montana, Heron, the highway runs east to N ...

(MT 200), and US 2. By 1947, it had been rerouted to run concurrently with US 95, as the majority of its former route had been replaced by the western extension of US 2 from

Bonners Ferry, Idaho Bonners Ferry (Kutenai language: ʔaq̓anqmi) is the largest city in and the county seat of Boundary County, Idaho, Boundary County, Idaho, United States. The population was 2,543 at the 2010 United States Census, 2010 census. The Porthill-Ryk ...

, to

Everett, Washington Everett (; ) is the county seat and most populous city of Snohomish County, Washington, United States. It is north of Seattle and is one of the main cities in the Seattle metropolitan area, metropolitan area and the Puget Sound region. Everett ...

. This change led the highway to begin in

Coeur d'Alene, Idaho Coeur d'Alene ( ; ) is a city and the county seat of Kootenai County, Idaho, United States. It is the most populous city in North Idaho and the principal city of the Coeur d'Alene Metropolitan Statistical Area. The population was 54,628 at th ...

, rather than in Seattle. It would remain in this configuration until its decommissioning in 1967, as

I-90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain states, Mountain West, Great Pla ...

gradually replaced US 10.

Route description

Washington

US 10A split from US 10 in

Seattle Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...

. The highway would then follow US 99 (modern

Washington State Route 99 State Route 99 (SR 99), also known as the Pacific Highway, is a state highway in the Seattle metropolitan area, part of the U.S. state of Washington. It runs from Fife to Everett, passing through the cities of Federal Way, SeaTa ...

) north to Everett. There it separated from US 99. It then traveled east across the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington (state), Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as m ...

via

Stevens Pass Stevens Pass (elevation ) is a mountain pass through the Cascade Mountains located at the border of King County and Chelan County in Washington, United States. U.S. Route 2 travels over the pass, reaching a maximum elevation of . The Pacific ...

to central Washington. In

Spokane Spokane ( ) is the most populous city in eastern Washington and the county seat of Spokane County, Washington, United States. It lies along the Spokane River, adjacent to the Selkirk Mountains, and west of the Rocky Mountain foothills, south ...

, the highway followed US 195 to

Sandpoint, Idaho Sandpoint is the largest city in, and the county seat of, Bonner County, Idaho, Bonner County, Idaho, United States. Its population was 9,777 as of the 2022 United States census, census. Sandpoint's major economic contributors include forest pr ...

Idaho

In Idaho, US 10A went through Bonner County and the town of

Sandpoint Sandpoint is the largest city in, and the county seat of, Bonner County, Idaho, United States. Its population was 9,777 as of the 2022 census. Sandpoint's major economic contributors include forest products, light manufacturing, tourism, recre ...

. In Sandpoint, US 10A intersected US 95. At the intersection, US 195 terminated, and US 10A would follow the shore of

Lake Pend Oreille Lake Pend Oreille ( ) in the northern Idaho Panhandle is the largest lake in the U.S. state of Idaho and the 38th-largest lake by area in the United States, with a surface area of . It is long, and deep in some regions, making it the fifth-deep ...

, serving the communities of

Hope Hope is an optimistic state of mind that is based on an expectation of positive outcomes with respect to events and circumstances in one's own life, or the world at large. As a verb, Merriam-Webster defines ''hope'' as "to expect with confid ...

and Clark Fork before entering Montana.

1947 reroute

After its reroute in 1947, US 10A started in Coeur d'Alene concurrent with US 95. It would follow US 95 north to

. At the intersection with US 2, US 10A spilt from US 95 and went east toward Clark Fork.

Montana

In Montana, the route would then follow through rural northwestern Montana and the towns of

Plains In geography, a plain, commonly known as flatland, is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, an ...

and Thompson Falls parallel to the Clark Fork and Flathead rivers. It then intersected US 93 in Ravalli. It then ran concurrently with US 93 south to Wye, where US 10A ended at Desmet Junction intersecting US 10 and US 93.

History

US 10A was formed in 1941 as an alternate route of US 10 going through northwestern

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, northern

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

, and central

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

. In Washington, it would follow the former route of US 10 through Stevens Pass before it was rerouted in 1939. It served as an artery to isolated communities in those states, such as

Clark Fork, Idaho Clark Fork is a small town in Bonner County, Idaho. The population was 536 at the time of the 2010 census. Geography Clark Fork is situated on the Clark Fork River, on the eastern shores of Lake Pend Oreille. in the northern panhandle of th ...

;

Plains, Montana Plains ( Salish: ncc̓kʷi) is a town in Sanders County, Montana, United States. The population was 1,106 at the 2020 census. It was founded as ''Horse Plains'' and sometimes called ''Wild Horse Plains'', as the local Native Americans would wi ...

; as well as several small towns in central Washington. It also replaced MT 3. In 1946, representatives of the highway departments of Idaho and Washington proposed an extension of US 2 to Everett that was considered by the

American Association of State Highway Officials The American Association of State Highway and Transportation Officials (AASHTO) is a standards setting body which publishes specifications, test protocols, and guidelines that are used in highway design and construction throughout the United St ...

's U.S. Route Numbering Committee in January 1946; however, the committee vetoed the proposal. The proposal resurfaced during the committee's meeting on December 20, 1946, and US 2 was approved as a replacement for US 10A from Everett to Sandpoint and US 195 from Spokane to Newport; however, US 195 would remain on road maps in Washington until at least 1951. In 1947, following the extension of US 2, US 10A was rerouted to start in Coeur d'Alene along US 95. I 90 Montana Construction sign

US 10A was decommissioned in 1967, as its parent route, US 10, was being replaced by

Interstate 90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain states, Mountain West, Great Pla ...

(I-90). After its decommissioning, the states of Idaho and Montana had replaced the former US 10A route with state highways. Montana renumbered MT 20, which had already been routed on US 10A by 1956, to MT 200. Idaho established SH-200 to replace US 10A a year later. Both highways were a part of a series of similarly numbered routes in

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

and

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

with the end goal being a unified federal designation.

Major intersections

1947 rerouting

Notes

References

External links

{{DEFAULTSORT:U.S. Route 10 Alternate (Washington-Montana) Alternate (Washington–Montana) 10 Alternate 10 Alternate 10 Alternate 10 Alternate (Washington–Montana) 10 Alternate (Washington–Montana) Transportation in King County, Washington Transportation in Snohomish County, Washington Transportation in Chelan County, Washington Transportation in Spokane County, Washington Transportation in Pend Oreille County, Washington Transportation in Bonner County, Idaho Transportation in Sanders County, Montana Transportation in Lake County, Montana Transportation in Missoula County, Montana Transportation in Kootenai County, Idaho