You can be driving through what appears to be the middle of nowhere when you see it. With no explanation as to its presence in that place, you will find a massive concrete arrow laying on the ground. It points toward — who knows?

Thousands of these arrows exist throughout the United States. The strange markers are in varying states of disrepair, with some being barely discernible amidst ground cover or from disintegration.

What are these arrows? What are they pointing toward? Who put them there? To find the answer to these questions, we must navigate our way through the early days of aviation, mail delivery, and the ever-present desire to speed up the means of communication.

Mail delivery has always attempted to employ cutting-edge methods to increase the speed of its service. The Pony Express, Transcontinental Railroad, and automotive delivery systems fueled the public’s desire to communicate and do business over long distances in as little time as possible. It did not take long after the Wright Brothers’ historic first flight before the plans for mail delivery envisioned the use of the airplane.

On June 14, 1910, Texas Congressman Morris Sheppard introduced legislation to authorize the Postmaster General to investigate the feasibility of “an aeroplane or airship mail route.” The bill died in committee. Evidently, not everyone had confidence in the newfangled flying machines. The New York Telegraph scoffed at the concept, saying that the notion might as well be envisioned as “Love letters will be carried in a rose-pink aeroplane, steered by Cupid’s wings and operated by perfumed gasoline. … [and] postmen will wear wired coat tails and on their feet will be wings.”

Postmaster General Frank Hitchcock was one person who saw promise in airmail. As an experiment, he authorized mail flights from Garden City Estates, New York to Mineola, New York. Eight pilots were sworn in as “aeroplane mail carriers.” From September 23 to October 1, 1911, the pilots flew bags of mail, dropping them from the plane to the ground, where an awaiting representative of the Postal Service took custody.

It wasn’t until 1917 that Congress got around to appropriating funds to establish a permanent airmail service. Through an arrangement between the Postmaster General and the Secretary of War, Army Signal Corps pilots and planes were assigned to start regular airmail serve between New York City and Washington, D.C.

Early attempts at involving airplanes in coast-to-coast mail delivery divided the responsibilities with trains. Pilots flew the mail as far as possible during daylight hours. As the sun started to set, the pilots landed near a railroad depot and offloaded the mail to a train. The train took over during the night hours until again handing the mail off to a waiting plane once there was enough light to be able to see. Using this method, a letter could make it from one coast to the other in 79 hours. When you consider that a train, without the help of an airplane, could accomplish the same task in 108 hours, there didn’t seem to be a lot about the airmail system to get excited about.

An all-airplane airmail delivery from San Francisco to New York was attempted on February 22, 1921. This was the first time mail flew during the night as well as day. The flight was successful, and Congress responded by appropriating $1,250,000 in support of expanded nighttime delivery of the mail.

The problem with regular nighttime flying was navigation. In those early days of aviation, pilots navigated by dead reckoning, using visual landmarks to help keep them on course. Radar, wireless communication, and other navigational tools were yet to be available. Consequently, efforts to fly in darkness or during bad weather had a nasty tendency to result in pilots getting lost and getting dead. On average, airmail pilots spent 900 hours in flight before being permanently retired by a fatal crash. The practice was so hazardous, in fact, that President Warren G. Harding considered prohibiting airmail altogether.

If airmail over long distances was to be successful, something had to be done to allow pilots to fly at night without getting lost or endangering themselves. The answer came in the form of the Transcontinental Airway System. The ambitious plan was almost comical in its simplicity.

The first segment was 885 miles between Chicago and Cheyenne, Wyoming. Its location permitted aircraft to depart from either coast in the morning and reach the lighted airway before night. Emergency landing fields were constructed every 25 miles, clearly identified by revolving beacon lights that could be seen for up to 80 miles. Between these fields, at 3-mile intervals, 289 flashing gas beacons — each visible for up to 9 miles — clearly showed the way through the air corridor. The beacons were spaced closer together near mountainous terrain and further apart in flat, open plains.

Beacon stations were developed for night and poor visibility flying conditions. They are sites along an airway that consisted of a rotating navigational beacon. Most were placed on a skeleton tower approximately 50 feet in height and powered by a generator, gas, or local power and used by air mail pilots for night flying. Each beacon had an identifying number so pilots could locate their precise positions on a map.

Once the Cheyenne to Chicago stretch was completed, new routes came online. In 1926, arrows were added to the beacons, pointing the way to the next higher numbered beacon. The first arrows were concrete and whitewashed. The control shed roof was painted white on the right side of the gabled ridge and red on the left. Black beacon numbers were painted on the white side of the shed roof, and white route numbers were painted on the red side of the shed roof.

From 1926 to 1932, the majority of the arrows were constructed out of concrete and were 57 feet long. Around 1932, arrows started to be made out of metal. By 1933, the Transcontinental Airway System covered 18,000 miles (29,000 km) and consisted of more than 1,500 beacons.

The system, though childishly simple, was ingeniously effective. The time for delivery of coast-to-coast mail plummeted to a mere 35 hours. As the consistency of the service improved, so did the value. The cost for postage to send a letter from coast to coast was 20 cents. Adjusted for inflation, that is the equivalent of about $3.12 in 2021; certainly affordable for the average American.

The savings were also seen in terms of human life. The new system allowed pilots to fly safely, efficiently, and accurately. It worked so well that engineers started to work on plans to build transoceanic airways, using lighted floating barges.

1933 saw the height of the Transcontinental Airway System. By then, advancements in navigation and radio technology started to make the arrows and ground lights obsolete. The Great Depression took its toll on the costly system. With the arrival of World War II, many of the beacons were dismantled to prevent any enemy bombers from using them to more easily find their targets.

The last airway beacon was officially shut down by the Federal Aviation Administration in 1973. The Montana Department of Transportation Aeronautics Division took control of seventeen beacons and continued to operate them into the 21st century. Citing budgetary concerns, fourteen of the beacons were shut down in 2018, with a commitment to shut down the rest by the end of 2021. As of this writing, the state is seeking the listing eight of the beacons in the National Register of Historic Places.

As for the rest of the navigational guides, many of them remain in various states of disrepair. The website Arrows Across America is dedicated to collecting photographs of these remnants of a once-proud transcontinental network. Visit the site to view the photographs, learn more about the history of the Transcontinental Airway System, and consult an interactive map to find the arrow closest to you.