KCSM Jazz91 FM, located in San Mateo, California, is a renowned brand in the world of jazz music. Established in 1964 as a student broadcast training facility, it has now evolved into a full-service radio station with a dedicated professional staff. KCSM operates 24 hours a day, offering a 24-hour jazz format that sets it apart from other stations in the Bay Area.

With a potential audience of over 6 million people, KCSM has become one of the top 35 most listened to non-commercial stations in the United States. As an affiliate of Public Radio International and National Public Radio, KCSM provides a platform for seasoned jazz musicians, educators, and broadcasters to host a diverse range of programs. The station's growing audience, which currently exceeds 200,000, is captivated by the exceptional playlists, exclusive interviews, and insightful content.

Apart from its engaging on-air content, KCSM also encourages community involvement through donations, support for car donations, and volunteer opportunities. KCSM Jazz91 FM continues to uphold its mission of promoting jazz music and serving as a learning laboratory for students enrolled in the College of San Mateo Digital Media Department. With its commitment to excellence and its unique dedication to jazz, KCSM is a beloved brand that stands at the forefront of the jazz scene