A relay league is a chain of message forwarding stations in a system of optical telegraphs, radio telegraph stations, or riding couriers.

An interesting description of these early 19th century methods and its evolution into the electrical telegraph

Electrical telegraph

An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via telecommunication lines or radio. The electromagnetic telegraph is a device for human-to-human transmission of coded text messages....

 networks of the mid-to-late 19th century is found in The Victorian Internet, a book by Tom Standage ISBN 0425171698.

Radio relay leagues

Radio amateur

Amateur radio

Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...

s have been early in arranging relay leagues, as is reflected in the name of the organization of American Radio Relay League

American Radio Relay League

The American Radio Relay League is the largest membership association of amateur radio enthusiasts in the USA. ARRL is a non-profit organization, and was founded in May 1914 by Hiram Percy Maxim of Hartford, Connecticut...

 (ARRL), http://www.arrl.org/.

Radio amateur message relay operations were originally conducted using Morse code

Morse code

Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...

 in the first two decades of the 20th century using spark-gap transmitter

Spark-gap transmitter

A spark-gap transmitter is a device for generating radio frequency electromagnetic waves using a spark gap.These devices served as the transmitters for most wireless telegraphy systems for the first three decades of radio and the first demonstrations of practical radio were carried out using them...

s. As vacuum tube

Vacuum tube

In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...

s became affordable operations shifted to more efficient manual telegraphy transmitters, referred to as CW (Continuous wave

Continuous wave

A continuous wave or continuous waveform is an electromagnetic wave of constant amplitude and frequency; and in mathematical analysis, of infinite duration. Continuous wave is also the name given to an early method of radio transmission, in which a carrier wave is switched on and off...

). Messages were relayed station to station typically covering four or more re-transmission cycles to cover the continental United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, in an organized system of amateur radio networks. After World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, voice and radioteletype

Radioteletype

Radioteletype is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations, later superseded by personal computers running software to emulate teleprinters, connected by radio rather than a wired link.The term radioteletype is used to...

implementations of the message relay system were employed.