KDNL-TV (channel 30) is a television station in St. Louis, Missouri, United States, affiliated with ABC. Owned by Sinclair Broadcast Group, the station maintains studios at the University Tower in the suburb of Richmond Heights and a transmitter in Shrewsbury.

Channel 30 in St. Louis was sought on several occasions in the 1950s and early 1960s, though no station materialized. The fourth attempt to build the channel was originally spearheaded by a group of local investors as well as Washington attorney John Dean; after the construction permit for KDNL-TV was sold to Thomas Mellon Evans, the station began broadcasting on June 8, 1969. It served as the second independent station for the St. Louis area, airing syndicated reruns as well as financial news and sports. Cox Broadcasting purchased KDNL-TV in 1981, in part because it held a permit for over-the-air subscription television broadcasting. Cox launched this service in June 1982, but it was a business failure, and Cox shut it down in February 1983. The station continued to be an overall money-loser and a misfit in the Cox station portfolio, even though it became the first local affiliate of Fox in 1986.

Barry Baker and Larry Marcus, former executives of rival independent KPLR-TV who were fired for trying to buy that station, purchased KDNL-TV from Cox in 1989. It became the first station in a St. Louis-based company eventually known as River City Broadcasting, which soon acquired other independent and Fox-affiliated stations. Ratings and revenue improved with the success of the Fox network, with total viewership approaching KPLR-TV, and led the station to start a local news department in January 1995. Under a deal announced in 1994 but carried out in August 1995, KDNL-TV lost its Fox affiliation and switched with KTVI to become the affiliate of ABC in St. Louis.

In 1996, River City merged into Sinclair Broadcast Group. However, KDNL's news department failed to gain traction, hurt by the traditionally poor ratings for ABC programming in the market; high turnover in news talent; a lack of full-day news service; and the resistance to change of many St. Louis viewers. In 1999, Baker left Sinclair and assigned an option to purchase KDNL-TV and six Sinclair-owned radio stations in St. Louis to Emmis Communications; the option resulted in a lawsuit settled with Sinclair retaining the TV station and selling off the radio properties. More critically, it led to neglect of the station's transmitter facility, causing signal issues, and the suspension of early evening newscasts for the struggling news operation. In the wake of the advertising slump after the September 11 attacks, Sinclair closed the KDNL-TV news department in 2001 and laid off all 47 staff. Since then, the station has largely been the fourth- or fifth-rated station in the market, with two short-lived and outsourced attempts at local news programming since the 2001 newsroom closure.

Three different attempts were made to start channel 30 in St. Louis. The assignment was added in 1952 when the Federal Communications Commission (FCC) ended its nearly four-year freeze on new television stations and introduced assignments in the new ultra high frequency (UHF) band. Applications were filed by the Empire Coil Company and the Lutheran Church–Missouri Synod for the channel, with the latter receiving the construction permit in February 1953 after Empire Coil withdrew. The church planned to run KFUO-TV as a noncommercial station in conjunction with its existing radio station. While it initially planned an early 1954 start, the station project was said to still be in consideration by February 1954, and the church surrendered the permit for cancellation in January 1956 after finding the potential for a UHF station poor.

In September 1956, the Plaza Radio and Television Company of New York applied for channel 30. Plaza also applied for authority to broadcast subscription television (STV) programming using the proposed station. The FCC indicated it would need to hold hearings to determine whether the channel should be awarded, even though no other group was seeking channel 30, because Plaza held but was not using a permit for channel 26 in San Francisco. This application and another for a station in Detroit were dismissed by the FCC in September 1958.

For the third time, channel 30 in St. Louis was sought when Washington, D.C.–based Globe Television Corporation filed to build the station in June 1964. The two leading stockholders in Globe were lawyers: Vincent B. Welch and Edward P. Morgan of the Washington firm of Welch, Mott & Morgan. Welch had founded the communications law firm in 1946, and Welch and Morgan were applying for new television stations nationwide, including Minneapolis; Columbus, Ohio; and Henderson, Nevada. The Welch–Morgan group was awarded the St. Louis permit and stations in Miami and San Jose, California, in October 1964. Globe Television renamed itself the Continental Summit Television Corporation after the permit was awarded; in June 1965, the company requested an extension of time to build. It stated that the Missouri Pacific Building, its intended transmitter site, was inadequate, as downtown office buildings interfered with the signal in the Illinois portion of the metropolitan area. It also requested that its application be switched from channel 30 to 24, which was inserted as part of a national overhaul of the UHF table of allocations that year.

Boyd Fellows, the former general manager of educational station KETC and assistant to the president of Continental, then left that company to become the president of a new firm seeking channel 30, the Greater St. Louis Television Corporation. Other officers included a Black dentist, Dr. Benjamin F. Davis, and a Washington attorney, John Dean; his then-wife, Karla Hennings, was also a stockholder. Dean had participated in the formation of Greater St. Louis Television Corporation in January, while he was still employed by Welch & Morgan; when the firm found out about the work, it dismissed Dean for what Welch called "unethical conduct". Though characterizations of his dismissal varied, one former associate told the St. Louis Post-Dispatch that he was ordered to leave immediately and not given time to pack up his belongings. This story came to light during the Watergate hearings, during which Dean was a crucial witness as to the cover-up of the Watergate scandal, and was first reported by syndicated columnist Jack Anderson.