WCHI-FM (95.5 MHz) is a mainstream rock formatted radio station located in Chicago, Illinois, owned and operated by iHeartMedia.

[4] The station began broadcasting on March 9, 1959 as WDHF, owned by Hi-Fi systems and record store owner James deHaan.

[2] Under deHaan's, Newhart's and the National Science Network's ownership, WDHF aired an easy listening/big band format.

[20] As a promotional stunt, in the days leading up to the format change the station periodically interrupted the rock programming with static and a man's voice stating "enough is enough".

[36][37] WNUA was the home of the now-defunct Ramsey Lewis morning show, and it was also where he recorded his syndicated show, Legends of Jazz (which showcased the music of instrumentalists Charlie Parker, Oscar Peterson and Miles Davis, as well as vocalists Louis Armstrong, Billie Holiday and Ella Fitzgerald) for distribution to other smooth jazz stations across the nation.

[41][42] Other on-air staff included Karen Williams, Rick O'Dell, Danae Alexander, Dave Koz, Bill Cochran, Scott Adams, Annie Ashe, Dona Mullen, Glenn Cosby, and Porsche Stevens.

"[54] Along with the clock sound, they aired a recap of jingles and moments from its history as WDHF, WMET, WRXR, and WNUA.

[54][55][32] The Smooth Jazz format was picked up a few hours later by television station WLFM-LP (Channel 6), whose audio is available on 87.7 FM.

[61] WEBG would serve as the Chicago affiliate of The Bobby Bones Show, first in evenings on a delay before being moved to mornings in August 2018.

[64] On September 3, 2020, at 11 a.m., after playing "Happy Trails" by Roy Rogers, WEBG began stunting with music from various genres (the first song being "It's the End of the World as We Know It (And I Feel Fine)" by R.E.M.

The format, while playing similar music to what it had during the days of WDHF, WMET, and even WRXR, also features a variety of rock reaching into the 1990s and as far as the late 2000s.

[69] On September 14, 2020, iHeartMedia announced that Angie Taylor from sister station WKSC-FM would host mornings on WCHI, alongside Abe Kanan.

[70] After a social media campaign for the slot, night host Maria Palmer was moved to mornings alongside Matthew (Marris) Harris and Michael Mason.

When WNUA signed on HD Radio operations in 2006, the station's HD2 sub-channel aired a traditional jazz format.