Less well-known than contemporary routes such as the Lincoln Highway, the Jefferson Highway, and the National Old Trails Road, the King of Trails Highway was nevertheless a popular early-twentieth-century cross-country highway route, and it passed right through the Allen County cities of Iola and Humboldt.
The King of Trails Association was established in 1917 to promote a route from Winnepeg Canada to Mexico. The route was marked by upwards of 14,000 painted poles to guide travelers, each marked with a black “K-T” on a yellow band.
As of 1917, the route was 319.4 miles in Kansas, with 51 miles hard-surfaced, 46 miles paved within cities, and 222.4 miles of “well graded and drained dirt road”.
Here’s a page describing the route, from the Parsons Sun newspaper, in 1922. Parsons was home of the King of Trails Association headquarters at that time:
Here’s a close-up of the King of Trails Highway Map:
Here’s a portion of the 1921 Atlas and Plat Book of Allen County, showing the King of Trails Highway route between Iola and Humboldt. This route would eventually become US-169 highway, and today is known as “Old 169”:
(Note also that the route is also labeled “Old Trails Hwy”; we’re not sure what this is, it does not seem to be part of the “National Old Trails Road”.)