Interest in providing access to Lewis and Clark’s expedition route grew in the 1920s. Although railroads existed throughout the west, there was not a significant highway network. Historians, like Wallace G. Lewis, noted that highways might provide easier access to the trail taken by Lewis and Clark.
The genesis of today’s auto tour route can be traced back to 1929. As automobiles grew in popularity throughout the 1920s, the federal government decided to increase funding for construction of long-distance highways in the western United States.
By the early 1960s, the Department of the Interior joined the efforts to establish an official auto route. In 1962, Secretary Stewart L. Udall directed the Bureau of Outdoor Recreation to work with federal, state, and local agencies to plan an official auto route.
In 1965, the Lewis and Clark Trail Commission approved a sign for the Lewis and Clark Trail highway. Before this date, the auto route was marked in a myriad of ways, but the commission sought to unify the auto route under a single marker.
As highways continued to expand, congressmen realized the potential tourism they could provide. One such congressman was Washington Senator Warren Magnuson, who in 1950 led the first congressional effort to establish an official roadway for Lewis and Clark’s expedition trail.
