Radio broadcasting has been used in the United States since the early 1920s to distribute news and entertainment to a national audience. In 1923, one percent of U.S. households owned at least one radio receiver, while a majority did by 1931 and 75 percent did by 1937. It was the first electronic "mass medium" technology, and its introduction, along with the subsequent development of sound films, ended the print monopoly of mass media. During the Golden Age of Radio it had a major cultural and financial impact on the country. However, the rise of television broadcasting in the 1950s relegated radio to a secondary status, as much of its programming and audience shifted to the new "sight joined with sound" service.
Originally, the term "radio" only included transmissions freely received over-the-air, such as the AM and FM bands, now commonly called "terrestrial radio". However, the term has evolved to more broadly refer to streaming audio services in general, including subscription satellite, and cable and Internet radio.
Overview +United States Broadcasting Station TotalsSources: 1922–1970: "Radio and Television Stations" Historical Statistics of the United States (volume 2), 1989; 1980: "Broadcasting Since 1949", 49th Annual Report of the Federal Communications Commission, 1983, pp. 93–94; 1990–2010: "Broadcast Station Totals" (Excel spreadsheet), FCC.gov; 2020: "Broadcast Station Totals As Of September 30, 2020" (FCC.gov) FMDateAMCommercialEducationalLow Power192230 1930618 1940847 3 (Apex band) 19502,14469162 19603,483741165 19704,2882,126416 19804,6893,3901,156 9/30/19904,9784,3571,435 9/30/20004,6855,8922,140 9/30/20104,7846,5123,2518649/30/20204,5606,7044,1962,143"Broadcast Station Totals as of September 30, 2025", FCC Publc Notice, DA 25-964, Released: November 25, 20259/30/20254,3436,5944,7301,985
Radio communication in the United States is regulated by the Federal Communications Commission (FCC). Under its oversight a variety of broadcasting services have been developed, including: Over-the-air services
AM band: When radio broadcasting first became popular in the 1920s, it was primarily within what is now the AM broadcast band, which spans from 540 to 1700 kHz.530 kHz is reserved for low-power travelers' information stations. The frequencies above 1610 kHz, also known as the AM expanded band, were not made available until the 1980s. The AM band continues to be used, with the most powerful clear-channel stations granted a coverage area at night of hundreds of kilometers from their transmitters, when atmospheric conditions carry AM skywave signals greater distances, by reflecting signals, that would otherwise head into space, back to Earth. Less powerful stations share frequencies and may either shut down, reduce power and/or change their directional patterns to avoid interference at and near sunset, flipping back at sunrise. Before television, AM radio was the predominant broadcast entertainment medium in America. Beginning in the 1970s, AM listenership has significantly declined, primarily shifting to the FM band. Because of this, the FCC allows some AM stations to simulcast their programming, and in some cases extend their hours of operation, over translator stations operating on the FM band. Shortwave: Shortwave broadcasting in the United States, also known as "high frequency", dates back to the 1920s, though the shortwave bands were nationalized during World War II and were not opened to private broadcasters again until 1962. Like AM, shortwave stations benefit from atmospheric propagation and can cover vast areas of territory, but the higher frequencies are reflected during the daytime and require the stations to shift frequencies depending on time of day, which discourages listening for long periods of time. Current services include federal government transmissions, such as the official time signal broadcasts over station WWV, plus a few privately owned outlets that focus primarily on brokered programming, religious broadcasting and alternative political talk, with some exceptions. The most widely known of the government-run networks is Voice of America, which features an international news and information format that serves a general worldwide audience; other networks target specific geographic regions. These government-run networks were, until 2013, forbidden from being marketed to American citizens; they still neither own nor affiliate with any AM or FM stations. The U.S. also provided the American Forces Network (AFN), a service for American armed service members stationed overseas that mostly relays commercial programming; AFN broadcasts are pointed away from the U.S. with signals pointed toward listeners in Japan, Korea and parts of Europe, and used single sideband technology to discourage casual American listeners from intercepting the programming. AFN appears not to have operated on shortwave since the mid-2010s. The upper end of the shortwave band, approximately 27 MHz, constitutes the citizens band, which peaked in popularity in the 1970s and is reserved for personal communications. FM band: FM stations have the largest public audience. Commercial FM broadcasting stations were first authorized as of January 1, 1941, following seven years in which many of the same owners operated experimental AM stations in the apex or ultra-shortwave band (which was initially shared with experimental FM stations). Twenty frequencies (88.1–91.9 MHz) are reserved for non-commercial stations (mostly government-run, nonprofit or religious), with the other eighty (92.1–107.9 MHz) normally used by commercial stations (though non-commercial stations are allowed to broadcast in the band as well). 87.9 MHz is also authorized, although only for very low powers in very limited circumstances and is thus unused as of 2022. In addition, a few low-power channel 6 TV stations, whose audio transmissions are just below the standard FM band at 87.75 MHz, have been authorized as "FM6" operations, establishing de facto FM radio stations, which can also carry commercial programming. Due to their higher assigned transmitting frequencies, FM stations are generally limited to line-of-sight transmissions, and thus have a somewhat limited broadcast range. However, FM range can be somewhat extended depending on weather conditions, including cases of rare, poorly understood and unpredictable E-skip propagation. FM stations also benefit from greater bandwidth than AM or shortwave (thus higher fidelity and stereophonic sound) and a capture effect that reduces interference between two stations of unequal strength on the same frequency. Translator stations, which initially were used to extend an FM station's signal into fringe coverage areas, are now also used—often acting as the primary outlet—for relaying HD Radio and AM station's signals. Most low-power broadcasting in the U.S. is on the FM band. AM and FM digital transition: The FCC has been overseeing a transition by broadcasting stations from analog to digital transmissions. For TV stations, this was a mandatory change, and by 2021, virtually all broadcast TV stations were required to switch to digital. In contrast to TV, the switch to digital by AM and FM stations is voluntary. In 2002, the FCC adopted iBiquity's in-band on-channel (IBOC) technology, branded as HD Radio, for radio stations. This standard includes a "hybrid mode", which allows AM stations to simultaneously transmit both its standard analog signal, plus a digital version of the same programming. For FM stations, "hybrid mode" also provides the ability to transmit additional programming."In the Matter of Digital Audio Broadcasting Systems And Their Impact on the Terrestrial Radio Broadcast Service", (MM Docket No. 99-325), Federal Communications Commission, October 10, 2002. However, adoption has been limited, especially on the AM band. The FCC permits some HD transmissions to also be retransmitted by analog FM translator stations, which generally have far more listeners than the originating HD signal. These digital subcarriers are a subset of the broader subsidiary communications authority FM stations have to broadcast additional content. DTV radio: DTV radio consists of audio-only services carried over existing digital television systems; such as digital subchannels of over-the-air television broadcasters. Weather radio: the National Oceanic and Atmospheric Administration operates the NOAA Weather Radio service of over 1,000 stations nationwide, operating on its own small designated 162 MHz FM band.
Two way radio services take up most of the rest of the geomagnetic spectrum, including marine VHF radio, amateur radio, the aforementioned citizens band, the Family Radio Service and the General Mobile Radio Service. Unlike most one-way broadcast services, these services are generally limited to voice transmission.
With the exception of WWVB, a station mainly operating to allow electronic clocks to synchronize with the NIST atomic clock, the United States does not license longwave radio services. Unlike Europe, which established a longwave broadcasting band, the only other authorized use of longwave in the United States is the unlicensed low-frequency experimental radio band.
Wireline and subscription audio In contrast to the over-the-air terrestrial radio services, wireline and subscription audio services are not regulated for content by the FCC. Depending on the medium, the FCC may have some indirect and general jurisdiction over some technical aspects of these broadcasts.
Cable radio: Cable radio providers include Music Choice, Muzak, DMX, Sonic Tap and Canada-based Galaxie. CRN Digital Talk Radio Networks specialize in talk radio.John Allen Hendricks, and Bruce Mims, The Radio Station: Broadcast, Satellite, and Internet (CRC Press, 2014) Satellite radio: Direct-to-consumer satellite radio broadcasting was introduced in the United States in 1997; there is only a single provider, SiriusXM. Technical operations are licensed by the FCC but not content. Internet radio: although the Internet originally was used for only text and graphics, beginning in the early 1990s it was adapted to transmitting audio; improved dial-up modems and audio compression in the 1990s allowed Internet radio to be accessed by the average user years before video content, which generally requires a broadband connection. Many of the Internet radio offerings are retransmissions of existing AM and FM radio stations, however there are also examples of Internet-only services. The major providers of Internet radio in the United States include iHeartRadio and Audacy (both of which are owned by major terrestrial station ownership groups iHeartMedia and Audacy, Inc. respectively), Pandora (owned by SiriusXM), Apple Music and Spotify; Pandora, Apple Music and Spotify operate exclusively on the Internet, while iHeart and Audacy offer a mix of Web-exclusive content and relays of AM and FM radio stations. Also falling under the umbrella of Internet radio is the podcast, a form of pre-recorded, usually spoken-word content designed to be automatically downloaded to listeners.
Reach and prevalence