KTRH (740 AM) is a commercial radio station licensed to Houston, Texas. It airs a news/talk radio format and is owned by iHeartMedia, Inc. Its studios are along the West Loop Freeway (I-610) in the city's Uptown district. The transmitter site, a four-tower array, is in unincorporated Liberty County, off Cox Road in Dayton. KTRH is one of the oldest radio stations in the United States, first licensed to Austin on April 22, 1922. Programming is also heard on co-owned KODA's HD 2 subchannel at 99.1 MHz, and on the iHeartRadio platform. KTRH is Southeast Texas' primary entry point station for the Emergency Alert System.

KTRH broadcasts with 50,000 watts around the clock, the highest power permitted by the Federal Communications Commission for commercial AM stations. But because it transmits on AM 740, a Canadian clear channel frequency, the station uses a directional antenna to protect Class A station CFZM in Toronto. During the day, the station provides at least secondary coverage to most southeast Texas, as far west as Austin and San Antonio and as far north as College Station and Lufkin, as well as much of southwestern Louisiana. At night, to protect CFZM, the station switches to a directional pattern with a significant null to the east, concentrating the signal in Houston, the Golden Triangle and Victoria.

The station was first licensed, with randomly assigned call letters WCM on April 22, 1922; 103 years ago (April 22, 1922). It was started by the University of Texas at Austin. (Initially call letters beginning with "W" were generally assigned to stations east of an irregular line formed by the western state borders from North Dakota south to Texas. Call signs beginning with "K" went only to stations in states west of that line. In January 1923, the Mississippi River was established as the new boundary. After this date, stations in Texas began receiving call letters beginning with "K." This is why the earliest stations in Texas, such as WOAI San Antonio and WBAP Fort Worth, still carry W call signs.)

WCM was authorized to broadcast on both the "entertainment" wavelength of 360 meters (833 kHz) and the "market and weather" wavelength of 485 meters (619 kHz). In November 1924 the station was relicensed to broadcast on 1120 kHz. On October 30, 1925, the station was relicensed with the new call letters of KUT, now operating on 1300 kHz. In early 1927 the station was assigned to 1100 kHz, and a few months later was assigned to 1290 kHz. On November 11, 1928, under the provisions of the Federal Radio Commission's General Order 40, the station moved back to 1120 kHz.

The university ultimately decided that it could not afford the expense of operating a radio station, and in early 1929 sold KUT to a group that planned to convert it from an educational to a commercial station.

Jesse H. Jones, operator of the Rice Hotel (now the Post Rice Lofts) in Houston, Texas and owner of the Houston Chronicle, took over the station to meet its competition, the Houston Post, which was the first of the local papers with a radio affiliation (KPRC). In December 1929, the station's call letters were changed to KTRH (standing for The Rice Hotel), and its main studio was moved to Houston. (Simultaneously, station KGDR in San Antonio, Texas was renamed KUT and moved to Austin (now KJFK). In March 1930, the station began broadcasting from the Rice Hotel. KTRH aired shows from the Columbia Broadcasting System as part of its initial programming.

In mid-1934 KTRH shifted to 1330 kHz, which was followed late the next year by a move to 1290 kHz with 5,000 watts in the daytime and 1,000 watts at night. On March 29, 1941, with the implementation of the provisions of the North American Regional Broadcasting Agreement (NARBA), the stations on 1290 kHz were moved to 1320 kHz. The next year KTRH moved to its current frequency of 740 kHz, and got a boost in power to 50,000 watts.

In 1947, Houston's first FM station was added, 101.1 MHz KTRH-FM. The FM station mostly simulcast KTRH's programming when few people had FM radios.