SEATTLE — Yellow-and-black stickers indicating a donor to the local broadcaster KEXP are a common sight on bumpers and laptops in this music-loving town. But the venerable independent station found at 90.3 FM on Puget Sound airwaves would have to exhaust its sticker supply to thank its most recent donor.

On Monday, the 46-year-old station announced a bequest of just under $10 million from an anonymous donor known as Suzanne. The station’s executive director, Thomas Mara, believes it is the largest-ever gift to a single U.S. public radio station. The donation will create a permanent endowment, secure six months’ continuous cash reserves and fund a full-time education and outreach team.

While the nature of a 24-hour live radio station doesn’t easily allow for an all-hands office meeting, Mr. Mara, 54, described the jubilant atmosphere at the station after informing the staff via email. “It was deeply moving to simply watch people’s expressions,” he said. “A lot of smiling, head shaking, even some tears.”

Suzanne died in 2016 and her estate lawyers informed the station of the gift in February 2017. For the last year, the station’s leadership and board kept the gift under wraps while they received a crash course in setting up a permanent endowment.