A recent post by Ken Jennings (yes, the famous Jeopardy! champion and geography buff) on Condé Nast Traveler looks at giant concrete arrows that marked the Transcontinental Air Mail Route. Jennings’ post, This Really Exists: Giant Concrete Arrows That Point Your Way Across America, gives a bit of background about the air mail route and the arrows. It also includes a recreation of a 1920’s route map showing stops.
Unfortunately, it appears the recreated map mistakenly includes a stop in Byron, Illinois rather than Bryan, Ohio, which did have an air mail field from 1918-1927.
The Western New Mexico Aviation Heritage Museum website includes a diagram of the generator-powered beacon that sat atop the concrete arrow.
A post from the EAA Southern Utah Chapter 936 provides information about the locations of several arrows near St. George, Utah. This post also includes a 1924 route map – correctly showing Bryan, Ohio – that could be the source for the recreated map in Jennings’ post.
Another post, this one from BonnevilleMariner.com, chronicles an attempt to shoot photos of arrows in Utah from the air.
You can find more images of the arrows by doing a Google Images search.