During daytime hours, near-perfect ground conductivity gives WGN at least secondary coverage to almost two-thirds of Illinois (as far south as Springfield) as well as large slices of Wisconsin, Indiana, Michigan and Iowa.

[10] In 1926, WGN broadcast Sam & Henry, a daily serial with comic elements created and performed by Freeman Gosden and Charles Correll.

After a dispute with the station in 1927, Gosden and Correll took the program's concept and announcer Bill Hay across town to WMAQ and created the first syndicated radio show, Amos 'n' Andy.

[11] By the fall of 1928, the owners of the Tribune company and its sister publication, Liberty magazine, controlled two stations in addition to WGN in the Chicago area: WLIB and WTAS.

WGN joined with WOR in New York City, WXYZ in Detroit and WLW in Cincinnati to form the network, a rival to NBC and CBS.

[18] In May 1940, the Federal Communications Commission (FCC) announced the establishment, effective January 1, 1941, of an FM radio band operating on 40 channels spanning 42–50 MHz.

)[29][30][31][32][33] In November 1958, WGN became the first radio station in Chicago to broadcast helicopter traffic reports featuring Police Officer Leonard Baldy.

[34][35][36] Eleven years later, WGN suffered another helicopter-related tragedy when Flying Officer Irv Hayden and his pilot were killed on August 10, 1971, after their helicopter struck a utility pole in the Chicago suburb of Bellwood.

Some former personalities on WGN include longtime morning hosts Wally Phillips, Bob Collins, Spike O'Dell, Paul Harvey and Roy Leonard.

Late-night hosts over the years have included Franklyn MacCormack, Ed "Chicago Eddie" Schwartz, and the husband-and-wife team of Steve King and Johnnie Putman.

[43] Industry observers described Metheny's tenure as one that nearly destroyed the venerable WGN, with staff moves that included replacing a popular evening host with radio rookie Jim Laski, a Chicago politician and convicted felon.

Meier hosted four shows, which is believed to have caused a surge in interest among younger people, who traditionally rarely listened to WGN.

The final show was largely a retrospective of the program's 20 years on WGN radio; this occurred shortly after the replacement of much of the station's weekend lineup.

In November, after the firing of controversial program director Kevin Metheny, Tom Langmyer instructed staff to identify the station as "720 WGN".

Weekend hosts Jerry Agar and the "News Junkie" Sean Wasson left the station, in a shift towards more general and less controversial talk programming.

Overnight hosts Steve King and Johnnie Putman left WGN on December 9 after a week-long series of live "Farewell Celebration" shows.

In June 2013, Tribune Broadcasting CEO Larry Wert hired Jimmy DeCastro as WGN radio's president and general manager.

In addition, Bob Sirott and Marianne Murciano's program moved to the weekday lineup and Steve Cochran was announced to be returning to WGN.

[60] On May 21, WGN Radio announced that their schedule would change again effective May 27, 2014, which included the return of John Williams to the station; he would host his program from Minneapolis, where he continued to do an afternoon show for WCCO.

His time slot announced was 10:00 a.m. to noon, which moved then mid morning hosts Bill Leff and Wendy Snyder to the afternoon drive from 3:00-7:00 pm.

Garry Meier would be moved to WGN.FM, with Steve Cochran's morning show getting expended by 1 hour, and Bob Sirott and Marianne Murciano still having their noon-3:00 p.m.

[61] On June 5, 2014, the Chicago Cubs announced that radio broadcasts of its games would move from WGN to WBBM for the 2015 season under a seven-year deal.

[62] On November 20, 2014, Chicago media blogger Robert Feder reported that WGN management planned to end operation of both WGWG-LP and internet station WGN.FM on December 31, 2014.

Jonathan Brandmeier and Garry Meier were released and their programs canceled immediately, with repeat shows airing through the end of December.

[63] The station began using its new studios on Wacker Drive for news reports in May 2018,[64] with the final show originating from Tribune Tower on June 18, 2018.

Bob Sirott was hired to replace Steve Cochran during morning drive hours, longtime mid-day duo Bill Leff and Wendy Snyder were ousted, and at a later date, evening host Justin Kaufmann was let go as well.

Cuts from JAM jingle packages Top News, Talktrax, Talking Points, Non-Stop Power, You'll Like Our Style, Follow The Leader, Variety Pack, Nothing But Class, Ameritalk, and (rarely) The Only One are regularly featured in station identifications, sounders, and promotions.

Harvey's news and commentary shows were carried nationally by ABC Radio, although he was based in Chicago and the programs aired locally on WGN.

Shortly after Nexstar took control of WGN, the station began to broadcast national NFL play-by-play on Sunday afternoons from Compass Media Networks.

At night its signal spreads north to Hudson Bay, south to the Gulf of Mexico, west to Colorado, and east to the Atlantic Ocean.