In the beginning, before KWMR took its position at 90.5 on your FM dial, there was a small group of lefty idealists with a farfetched idea. They would start a radio station, even though none of them knew how.

Somehow, they did it. 

Next Thursday, which Marin County has proclaimed KWMR Day, the station will celebrate its 25th birthday with a party at the Dance Palace. Everyone is invited.

It was on May 2, 1999, that West Marin’s community radio station first went on the air with an official license from the F.C.C. With a crowd gathered in the Green Barn—then the Red Barn—former Supervisor Steve Kinsey and station co-founder Richard Dillman flipped a switch. Program director Aggie Murch turned on the transmitter in the closet-sized studio upstairs.

“This is KWMR!” the crowd shouted when Mr. Dillman pointed a mic in their direction. The David Thom Band struck up a bluegrass tune, and a station was born.

“It was amazing,” Mr. Dillman said, recalling the scene to the Light this week. “Putting any new radio station on the air for the first time is a fantastic experience, but this one was just orgasmically great.”

Four years before its official launch, a core group of radio stalwarts had begun broadcasting their shows on a Horizon Cable TV local access channel—not the sexiest place to build a fanbase, but better than nothing. Their fledgling audience had to tune into a blank T.V. screen to listen.

Soon the group rustled up some rudimentary radio equipment, and station founders Donna Sheehan, James Stark and John Gouldthorpe ran an ad in the Light, inviting others to join their campaign to get on the airwaves. It caught the attention of Ms. Murch, who had experience as a broadcaster on KPFA in Berkeley.

Word of their efforts also reached Mr. Dillman, a transmitter engineer who had helped put San Francisco community radio station KPOO on the air. One day, he and his friend Mariah drove up to West Marin to meet with the pioneers. They arrived with a tiny transmitter, a tape deck, a car battery and an antenna attached to his 1958 Jeep.

He hauled his equipment up a hill in Marshall, popped in a cassette and began playing Pavarotti to some cows as fog rolled in across Tomales Bay. The rest of the group drove around West Marin, tuning in to their temporarily pirated channel on their car radios. 

They heard it in Marshall. They heard it in Point Reyes Station. They heard it in Inverness. “It was thrilling,” Mr. Dillman said. “It was very emotional, and it really gave a kickstart to our project.”

The group redoubled its efforts to get an official spot on the dial, and it wasn’t too long before they did.

Community support came quickly, and it covered the very basic budget, which included a tiny salary for the first programming director, Kay Clements, who worked more than fulltime for puny part-time pay. 

As the station was getting off the ground, the 1995 Mount Vision fire made people acutely aware of the need for prompt and regular local emergency broadcasts.

“I was going door to door, asking for money,” recalled Mr. Gouldthorpe, who conducted on-air author interviews during the station’s early days. “It was month to month like that for years. I was grooming what we now call major donors, looking people in the eye and asking for $5,000 or $10,000. Surprisingly, people wrote checks.”

They still do.

“I came here 14 years ago, and it already felt like the station had been here a long time,” said Amanda Eichstaedt, KWMR’s executive director and station manager. “I would say 25 years is an accomplishment. We’re on solid footing. Our books are squeaky clean. We have good systems in place and we have great programming.”

As it has from the beginning, the station continues to play a quirky mix of programming, for KWMR is nothing if not idiosyncratic. There’s granular public affairs conversations, teen rap sessions, Hawaiian music, cowboy music, classical music, poetry readings, dramatic recitations of adventure stories and the latest news. There’s English programming, Spanish programming and regular bursts of sexy French. Even within the same show, you might hear Mozart one minute and Jimi Hendrix the next.

A youth D.J. project trains local students aspiring to become broadcasters. On a recent show, phone calls and random conversation entertained listeners between tracks.

Who’s calling? 

A friend from down the street!

What’s your name?

Lucy!

I knew it!

Oh, my god, bro, say hi to Maddie for me!

Happy Hour is a Friday evening staple once hosted by Liberacha, who shared her favorite cocktail recipes while playing old jazz standards. An on-air suitor who went by the name of Claude de Boozy called into the show and challenged to a duel anyone who might compete for her affections—which he eventually won in real life.

Feelings run deep on KWMR. Even its voicemail is ardent: “Hello, and thanks for calling KWMR, where the flame of true community radio burns with the white-hot intensity of a thousand suns.”

The station has over 100 homegrown programmers, most of whom are well behaved. During her 14 years at the helm, Ms. Eichstaedt has only had to let one of them go, after he rattled off three of the seven words you can’t say on television—or radio.

After the station got its F.C.C. license and an official spot on the FM dial, following the rules became a matter of particular concern for Peter Martinelli and Anthony Consani, who started the show “Off the Cuff” in the station’s earliest days. The show had a college radio vibe, mixing snippets of jazz, rock and country that might suddenly jump to a cartoon soundtrack. Outbursts of profanity from a comic’s sketch could cause problems if not properly screened.

“A major violation could have shut us down,” said Mr. Martinelli, who now hosts a country music show, Silver Dollar Jukebox, on Monday evenings. “We were really paying attention to make sure the songs were vetted.”

Over the years, the station broadened its reach, adding FM transmitters that broadcast to Bolinas at 89.9 and the San Geronimo Valley at 92.3. 

Anyone with a compelling idea can walk into the office and propose a show, and there’s a decent chance they will find themselves on the air after the requisite training.

The key to a successful show is passion, Ms. Murch said. “If you’re an Argentine neuroscientist who wants to play opera, if you’re a young man studying Korean poetry—come on the air,” she said. “If you’re crazy about what you do, your enthusiasm will draw people in. Radio is intimate. It’s just the two of you—you, and your audience.”