In 1978, Art Bell created and hosted West Coast AM, a late-night political talk/call-in show on Las Vegas radio station KDWN. In 1988, Bell and Alan Corberth renamed the show Coast to Coast AM and moved its studios from the Plaza Hotel in Las Vegas to Bell's home in Pahrump.[4] After Bell's retirement, the show was hosted by various personalities, including Mike Siegel, George Noory, and others.

At its peak, Coast to Coast AM under Bell was syndicated by Premiere Radio Network, and aired on more than 500 radio stations and boasted a weekly listening audience in excess of 10 million listeners.[5][6][7] Since 2013 the weekly listener numbers have declined to 2.5 million.[8] According to estimates by Talkers Magazine, Coast to Coast AM has a cumulative weekly audience of around 2.75 million unique listeners listening for at least five minutes, making it the most listened-to program in its time slot.[9] By 2010 the program was known as by far the most popular overnight show in the country,[2] echoed by The New York Times in 2017, citing Nielsen ratings.[3]

The show is estimated to be carried by over 600 US affiliates,[1] along with a limited number of FM stations, as well as many Canadian affiliates, several of which stream the show on their station's website. The affiliate group is fronted by 12 clear-channel stations, among them WBT in Charlotte, WHO in Des Moines, WWL in New Orleans, WOR in New York City, KFBK in Sacramento, and KFI in Los Angeles. The show is also carried by Sirius XM Radio, on its Road Dog Trucking channel 146

In broadcasting, a phone-in or call-in is a programme format in which viewers or listeners are invited to air their live comments by telephone, usually in respect of a specific topic selected for discussion on the day of the broadcast. On radio (especially talk radio), it is common for an entire programme to be dedicated to a phone-in session. On television, phone-in's are often part of a wider discussion programme: a current example in the UK is the "Jeremy Vine" TV show.