Transcontinental Airway And Wyoming’s Role In The Expansion Of Mail Service

Rock Springs Airport that was located at the current site of the Sweetwater County Events Complex.
Photo Credit: Sweetwater County Historical Museum

Many Sweetwater County residents are unaware of the role the county played in the expansion of mail service in the United States in the early 1900’s.  In fact, the county has four arrows still visible from the sky which aided pilots in their flights across the country.

The history of airmail flights dates back to 1911, when the United States Postal Service authorized the first ever experimental mail flight at an aviation show in Long Island, New York . By 1912, 52 flights had been authorized in more than 25 states at fairs, carnivals and air meets .

Between 1912 and 1916, the United States Postal Service urged Congress to appropriate money to launch airmail service. In 1916 Congress authorized a total of $50,000, but no aircrafts were received due to the absence of suitable planes. Congress approved another $100,000 in 1916 to establish experimental airmail routes, and the Post Office encouraged the Army Signal Corps to lend its planes and pilots to start the service. The Army argued that the cross-country flights would provide invaluable experience to the student pilots, and the Secretary of War agreed.

In October of 1919, General William “Billy” Mitchell, a staunch advocate of aviation, put together a U.S. Air service transcontinental air race. Although a number of pilots had flown across the United States since Cal Rodgers accomplished the feat in 1911, there were still no organized routes, and landing strips were slim to none, especially in the western U.S. The route used was later adopted by the Post Office as the most practical. Of the 48 planes that departed from New York, New York and the 15 that departed San Francisco, California, only 33 would complete a one-way crossing and only eight would make the full round trip. There were a total of seven pilots who lost their lives.

The routes were short at first, and the Post Office envisioned a transcontinental airmail route from New York to San Francisco to better its time on long hauls and to lure more people to use airmail. The first leg of the continental route was from New York to Cleveland in 1918; The Cleveland to Chicago leg was established in 1919; Chicago to Omaha in 1920; and the last segment Omaha to San Francisco was opened on September 8, 1920. This last leg included stops in North Platte, Cheyenne, Rawlins, Rock Springs, Salt Lake City, Elko and Reno.

    Google Maps Photo of Arrow Near present day TATA Chemicals

In an attempt to make night flying safer, the United States Postal Service in 1923 began building a series of lighted beacons between Cheyenne, Wyoming and Chicago, Illinois. This particular section was chosen partly because of its relatively flat terrain and proximity to commercial power.

More importantly, planes leaving New York City could reach Chicago by nightfall. Planes leaving San Francisco, California could land in Cheyenne, Wyoming before dark. Westbound flights could now fly cross country in 34 hours, while eastbound flights with their tailwinds only took 29 hours, beating the railroads by two days in some cases.

The state of Wyoming was surveyed by ground and air in the summer of 1923. Construction of the airway started in 1924. Airways were designated by the first letters of their terminal cities and read from west to east and south to north. They were designed so that no segment exceeded 1,000 miles and were subdivided into 100-mile sections. Wyoming fell within the Salt Lake to Omaha section of the route which was designated SL-O.

Fifty-four-foot concrete arrows pointing to the next higher numbered beacon—that is, the next beacon to the east—were installed as a way for pilots to find their way during the day. These were originally painted chrome yellow with an eight-inch black border.

There are a total of 14 different arrows and 10 beacons across the state with four arrows and three beacons located in Sweetwater County.

While under the administration of the federal government, the field had several classifications.

The beacons rotated at six revolutions per minute. Each drum style beacon housed a 24-inch parabolic mirror with a 1,000-watt Mazda lamp projecting 1,000,000 candlepower. The beam was elevated about one degree above the horizon and could be seen 40 miles away on a clear night.

In early 1931, advances in radio technology reached the tiny eastern Wyoming town of Medicine Bow, allowing pilots to fly coast to coast regardless of weather conditions.

The Medicine Bow low-frequency radio signal connected the radio beams from Rock Springs and Cheyenne, Wyoming, completing the route from San Francisco to New York. Pilots could now fly across the country safely and more efficiently than ever before. The event was a game-changer for aviation and the transcontinental airmail system. This process helped create the passenger airlines we rely on today.

The railroad had an important role, too, it helped pilots know that they were still on course. From the air, pilots would follow the tracks, they were known to the pilots as “the iron compass.” Often, the mail was carried on the airplanes part of the way and then transferred to trains for land transport.

On July 1, 1927, the Department of Commerce, Aeronautics Branch took over the U.S. Postal Service’s existing infrastructure and began to fulfill its congressional mandate to upgrade the nation’s airways.

By the fall of 1927, the airmail system ceased to be funded directly by the government and began to be operated by private contractors. The City of Cheyenne purchased a $600,000 facility and leased it to Boeing Air Transport, which had won the mail contract to San Francisco.

All information and images were provided by the Sweetwater County Historical Museum,, and

Airmail Plane Crash On White Mountain. Photo Credit Sweetwater County Historical Museum