What Is 420? The Real Story Behind the Cannabis Holiday

420, 4:20, or 4/20 — however you write it, the number has become a cultural icon. It shows up on T‑shirts, memes, festival posters, and even highway signs. But for something so widely recognized, surprisingly few people know where it actually comes from.

Over the years, plenty of theories have popped up. Some people swear it was a police code for marijuana use (it wasn’t). Others insist the Grateful Dead always booked hotel room 420 (also false). Another popular myth claims cannabis has 420 chemical compounds — in reality, it’s closer to 315.

So where did 420 really start? The truth is much simpler, and honestly, way more charming.

The Real Origin of 420: San Rafael, California, 1971

The story begins at San Rafael High School in Northern California. In 1971, a group of five friends — later known as The Waldos — started using “420” as their private code for anything related to cannabis.

Here’s the short version:

• The Waldos got a hand‑drawn map that supposedly led to an abandoned cannabis grow near Point Reyes.

• They agreed to meet after school at 4:20 p.m., by the Louis Pasteur statue on campus.

• They’d hop in a car, smoke, and go searching for the mysterious crop (which they never actually found).

• “420” became their inside joke and shorthand for smoking together.

It stayed a local secret for a while — until music culture helped it spread.

How 420 Went From Inside Joke to Global Symbol

One of the Waldos had a connection to Phil Lesh, the bassist of the Grateful Dead. As the friends hung around rehearsals and shows, the term “420” naturally slipped into the Deadhead community — a massive, devoted fan base that traveled from show to show.

The real turning point came in 1990, when a flyer circulated at a Dead concert in Oakland inviting people to meet on April 20 at 4:20 p.m. to smoke together. That flyer eventually landed on the desk of an editor at High Times, who published it in 1991.

From there, 420 exploded into mainstream cannabis culture.

By 1998, High Times officially credited The Waldos as the originators of the term.

420 Today: A Global Cannabis Celebration

Today, April 20 is recognized around the world as a day to celebrate cannabis, advocate for legalization, and gather at massive public events. Cities like Denver, Vancouver, and San Francisco host huge 4/20 festivals that draw thousands of people.

The number has become so iconic that in 2014, the Colorado Department of Transportation replaced the frequently stolen “Mile 420” highway marker with a sign reading 419.99 — a very creative solution to a very persistent problem.

Quick Summary

• 420 originated in 1971 with a group of high school students called The Waldos in San Rafael, California.

• They used 4:20 p.m. as their meetup time to search for a rumored cannabis grow.

• The term spread through the Grateful Dead community and was later amplified by High Times magazine.

• April 20 (4/20) is now a global cannabis holiday celebrated with events, activism, and gatherings.