XETRA-FM (91.1 MHz), branded as 91X, and sometimes identified as XTRA-FM, is an English-language radio station licensed to Tijuana, Baja California, Mexico.

On November 20, 1968, Radiodifusora del Pacífico, S.A. de C.V., then-owner of AM 690 XETRA (now XEWW), received a concession for a new FM station with the call sign, XETRA-FM on 91.3 MHz.

On September 5, 1978, XETRA-FM moved to 91.1 MHz and began broadcasting with 100,000 watts from a new transmitter site atop Mount San Antonio.

Initially, programming was recorded at the downtown San Diego studios in the Harcourt, Brace, Jovanovich Building and driven across the border to the transmitter site several times a day.

"[5] Ultimately, AOR would not last on 91X, and then-Executive Vice President and General Manager John Lynch would again reformat the station a few years later.

Immediately afterward, John Lynch made the announcement of the format change, and DJ Todd Ralston went right into "Sex (I'm a ...)" by Berlin.

[8] On February 6, 1996, Jacor Communications announced plans to acquire Noble Broadcast Group Inc, including the U.S. marketing and operating rights to 91X, for $152 million.

In December 2009, Finest City, faced with considerable debt and foreclosure, was forced to put the entire cluster up for sale after defaulting on a loan.

[13] On January 7, 2010, Local Media of America LLC, backed by private equity firm Thoma Bravo, emerged as the buyer in the foreclosure sale.

Lynch simultaneously owned Broadcast Company of the Americas, another cluster of border blaster stations in the San Diego/Tijuana market.

On October 6, 2015, Midwest Television (owners of KFMB and KFMB-FM) announced that it had entered into a joint operating agreement with Local Media San Diego LLC, forming an entity known as SDLocal, to manage their collective cluster of stations.

The intent of this short-lived agreement was to "[preserve the] local ownership and operation of San Diego's top-rated radio stations".

[21] On the evening of February 23, following the marathon's conclusion, XETRA-FM shifted its format to one focused more on 1980/1990s classic alternative while keeping the "91X" moniker, with the new slogan "The Original"; the move was officially announced on-air at 10 a.m. the following day.

[22] When Howard Stern was hosting a syndicated morning show on terrestrial radio, 91X was his original San Diego network affiliate.

He was pulled from XETRA-FM in 1997 and moved to then-sister station KIOZ after Stern's discussions ran afoul of the Dirección General de Radio, Televisión y Cinematografía, Mexico's broadcast content regulator.

RTC threatened to sanction XETRA-FM for airing Stern's program, which on several occasions in late 1996 included what the Mexican government believed were anti-Mexican remarks that violated the Federal Radio and Television Law.