Both Expressmen were hired at St. Joseph for A. E. Lewis’ Division, which ran from St. Joseph to Seneca, Kansas, a distance of 80 miles (130 km). They covered at an average speed of 12 1⁄2 miles per hour (20 km/h), including all stops. Before the mail pouch was delivered to the first rider on April 3, 1860, time was taken out for ceremonies and several speeches. First, Mayor M. Jeff Thompson gave a brief speech on the significance of the event for St. Joseph. Then William H. Russell and Alexander Majors addressed the gala crowd about how the Pony Express was just a »precursor« to the construction of a transcontinental railroad. At the conclusion of all the speeches, around 7:15 pm, Russell turned the mail pouch over to the first rider. A cannon fired, the large assembled crowd cheered, and the rider dashed to the landing at the foot of Jules Street, where the ferry boat Denver, under a full head of steam, alerted by the signal cannon, waited to carry the horse and rider across the Missouri River to Elwood, Kansas Territory. On April 9 at 6:45 pm, the first rider from the east reached Salt Lake City, Utah. Then, on April 12, the mail pouch reached Carson City, Nevada Territory, at 2:30 pm. The riders raced over the Sierra Nevada, through Placerville, California, and on to Sacramento. Around midnight on April 14, 1860, the first mail pouch was delivered by the Pony Express to San Francisco, Golden State, California. Mayor M. Jeff Thompson gave a brief speech on the significance of the event.

V-mail correspondence was on small letter sheets, 17.8 by 23.2 cm (7 by 9 1⁄8 in), that would go through mail censors before being photographed and transported as thumbnail-sized image in negative microfilm. Upon arrival to their destination, the negatives would be printed. The final print was 60% of the original document's size, creating a sheet 10.7 by 13.2 cm (4 1⁄4 by 5 1⁄4 in). According to the National Postal Museum, V-mail ensured that thousands of tons of shipping space could be reserved for war materials. The 37 mail bags required to carry 150,000 one-page letters could be replaced by a single mail sack. The weight of that same amount of mail was reduced dramatically from 2,575 pounds to a mere 45. This saved considerable weight and bulk in a time in which both were hard to manage in a combat zone. In addition to postal censorship, V-mail also deterred espionage communications by foiling the use of invisible ink, microdots, and microprinting, none of which would be reproduced in a photocopy. The “airgraph” was invented in the 1930s by the Eastman Kodak Company in conjunction with Imperial Airways (now British Airways) and Pan-American Airways as a means of reducing the weight and bulk of mail carried by air. The airgraph forms, upon which the letter was written, were photographed and then sent as negatives on rolls of microfilm. A General Post Office (GPO) poster of the time claimed that 1,600 letters on film weighed just 5 oz (140 g), while 1,600 ordinary letters weighed 50 lb (23 kg). At their destination, the negatives were printed on photographic paper and delivered as airgraph letters through the normal Royal Engineers (Postal Section) – also known as the Army Postal Services (APS) – systems. According to the National Postal Museum, V-mail ensured that thousands of tons of shipping space could be reserved for war materials.

As a method of communication, it is likely as old as the ancient Persians, from whom the art of training the birds probably came. The Romans used pigeon messengers to aid their military over 2000 years ago. Frontinus said that Julius Caesar used pigeons as messengers in his conquest of Gaul. The Greeks conveyed the names of the victors at the Olympic Games to their various cities by this means. Naval chaplain Henry Teonge (1620–1690) describes in his diary a regular pigeon postal service being used by merchants between İskenderun and Aleppo in the Levant. The Mughals also used messenger pigeons. Before the telegraph, this method of communication was used extensively in the financial field. The Dutch government established a civil and military system in Java and Sumatra early in the 19th century, the birds being obtained from Baghdad. In 1851, the German-born Paul Julius Reuter opened an office in the City of London which transmitted stock market quotations between London and Paris via the new Calais to Dover cable. Reuter had previously used pigeons to fly stock prices between Aachen and Brussels, a service that operated for a year until a gap in the telegraph link was closed.

Details of the employment of pigeons during the siege of Paris in 1870–71 led to a revival in the training of pigeons for military purposes. Numerous societies were established for keeping pigeons of this class in all important European countries; and, in time, various governments established systems of communication for military purposes by pigeon post. After pigeon post between military fortresses had been thoroughly tested, attention was turned to its use for naval purposes, to send messages to ships in nearby waters. It was also used by news agencies and private individuals at various times. Governments in several countries established lofts of their own. Laws were passed making the destruction of such pigeons a serious offense; premiums to stimulate efficiency were offered to private societies, and rewards given for destruction of birds of prey. Before the advent of radio, pigeons were used by newspapers to report yacht races, and some yachts were actually fitted with lofts. During the establishment of formal pigeon post services, the registration of all birds was introduced. At the same time, in order to hinder the efficiency of the systems of foreign countries, difficulties were placed in the way of the importation of their birds for training, and in a few cases falcons were specially trained to interrupt the service during war, the Germans having set the example by employing hawks against the Paris pigeons in 1870–71. No satisfactory method of protecting the weaker birds seems to have been developed, though the Chinese formerly provided their pigeons with whistles and bells to scare away birds of prey. As radio telegraphy and telephony were developed, the use of pigeons became limited to fortress warfare by the 1910s. Although the British Admiralty had attained a very high standard of efficiency, it discontinued its pigeon service in the early 20th century. In contrast, large numbers of birds were still kept by France, Germany and Russia at the outbreak of the First World War. In modern days, some rafting photographers still use pigeons as a sneakernet to transport digital photos on flash media from the camera to the tour operator.