From Secret Code to Global Holiday: The Real History of 4/20

For adults 21 and over.
Every April 20, “4/20” lights up storefronts, group chats, and city parks alike. It’s shorthand the whole world seems to know, but where did it actually come from? The real story has nothing to do with a police radio code or Bob Marley (two myths you’ll still hear repeated).
It starts with five teenagers, a hand-drawn map, and a legendary rock band. Here’s how a private inside joke from 1971 became a worldwide cannabis tradition, and how we mark it here in the Hudson Valley.

The Waldos and the treasure map

In the fall of 1971, a group of five friends at San Rafael High School in Marin County, California, called themselves “the Waldos”, not for anything cannabis-related, but because they liked to hang out by a particular wall on campus. As the story goes, they got hold of a hand-drawn map said to lead to an abandoned cannabis patch near the Point Reyes Peninsula, reportedly planted by a Coast Guard member who could no longer tend it.
The Waldos agreed to meet after sports practice at the campus statue of Louis Pasteur, at 4:20 p.m., pile into a 1966 Chevy Impala, and drive out to find it. They searched for weeks. They never found the patch. But the meeting time stuck.

From inside joke to secret code

“4:20” quickly stopped meaning just a meeting time. The Waldos started using “420” as all-purpose shorthand for cannabis, a way to talk about it in the hallways without tipping off teachers or parents. (One member’s father was reportedly a narcotics agent, which made discretion especially handy.) What began as a single afternoon’s plan turned into a private language the group carried with them.

How the Grateful Dead spread it

A high-school slang term usually stays at the high school. “420” didn’t, because the Waldos happened to be plugged into one of the era’s most influential music scenes. One
member’s older brother was friends with Grateful Dead bassist Phil Lesh, and that connection gave the group access to the band’s rehearsals, shows, and backstage world;
one Waldo even went on to work as a roadie.
As the term floated through the Dead’s enormous, devoted fanbase, the Deadheads, it traveled the country by word of mouth, concert to concert. By December 1990, fans were
handing out flyers at an Oakland show inviting people to smoke “420” on April 20. A High Times reporter picked up one of those flyers, the magazine ran with it, and the date was locked in.

Two myths, busted

Because the term spread by word of mouth, a couple of tall tales tagged along. Two are
worth clearing up:
• It’s not a police code. Despite a popular rumor, “420” was never the police radio code for cannabis in California or anywhere else, the number came straight from the Waldos’ 4:20 meeting time.
• Bob Marley had nothing to do with it. The date isn’t tied to the reggae icon’s birthday or passing, those fall on entirely different days.

A quick 4/20 timeline

From a high-school parking lot to the global stage, here’s how the number traveled:
• 1971: The Waldos coin “420” at San Rafael High School and start their search for the abandoned crop.
• 1970s–80s: The term spreads quietly through the Grateful Dead’s circle and the wider Deadhead community.
• December 1990: Flyers at an Oakland Dead show invite fans to gather for “420” on April 20.
• 1990s: High Times popularizes the term and the date in print, cementing 4/20 nationally.
• 2017: “420” earns an entry in the Oxford English Dictionary, recognized as part of the language.
• Today: April 20 is observed worldwide, from casual gatherings to major festivals and advocacy events.

4/20 today: celebration and call to action

From there, “420” went fully mainstream, it’s now even recognized by the Oxford English Dictionary. But the holiday has grown into more than a punchline. Today, April 20 is part celebration and part advocacy: a day to enjoy cannabis culture, but also to talk about legalization, social equity, and the people still affected by decades of prohibition. In a legal market like New York’s, it’s also a chance for communities to gather openly at licensed shops, something that would have been unthinkable when five kids were whispering a code in a California hallway.

How 4/20 is celebrated today

What started as a private code is now a global occasion, and it looks different depending on where you are:
• Community gatherings & festivals: public events with music, food, and education, especially in legal markets.
• Dispensary specials: many shops mark the day with deals, new product drops, and in-store events.
• Advocacy & awareness: organizations use the day to push for reform, expungement, and social equity.
• Low-key get-togethers: for plenty of people, it’s simply a relaxed day to enjoy with friends.
In a state like New York, 4/20 has taken on a new character: it’s the first time many communities can gather openly and legally at licensed retailers, a long way from whispering a code in a hallway.

4/20 in New York

New York’s legal market gives 4/20 fresh meaning. Adult-use cannabis became legal under the Marihuana Regulation & Taxation Act, signed in 2021, with licensed retail sales beginning in late 2022. That means New Yorkers 21 and older can now mark the day by shopping at OCM-licensed dispensaries, supporting legal, tested products and the equity goals built into the state’s program. For Hudson Valley locals, it’s a chance to celebrate close to home and get to know the shops in your own backyard.

How do we know this is the real story?

Plenty of origin myths have floated around over the years, so why does the Waldos’ account win out? Evidence. The group held onto physical proof from the early 1970s, letters, a flag, and other dated artifacts, that documents their early use of the term. No competing story has ever produced anything earlier or more credible. That paper trail is a big reason historians and the Oxford English Dictionary point to the Waldos as the origin, and why the once-anonymous group eventually stepped forward to tell it themselves.

Beyond 4/20: other cannabis dates

April 20 may be the headliner, but it’s not the only date cannabis culture marks:
• 7/10 (“710”): read upside down it spells “OIL,” so it’s become the unofficial day for concentrates and dabs.
• Local advocacy days: some communities recognize reform-focused dates tied to legislation and policy milestones.
None has the reach of 4/20, but together they show how a simple piece of slang grew into a whole calendar of cannabis culture.

Root 9: a Hudson Valley family celebration

At Root 9 Dispensary in Wappingers Falls, 4/20 is one of our favorite days of the year, and for us it’s less about the smoke than the people. As a family-owned shop, we’ve built our space around a welcoming vibe, a knowledgeable team, and a genuine love for helping neighbors find what works for them. Every April, we like to give back to the community that makes it all possible, from in-store specials to local events. Check our menu and social channels each spring for the current lineup.

4/20 FAQ

Why is 4/20 “weed day”?
Because of the Waldos’ 4:20 p.m. meeting time in 1971. The number became their code for cannabis, spread through the Grateful Dead’s community, and was popularized as April 20 by flyers and High Times.
Is 420 really a police code?
No, that’s a common myth. “420” came from the Waldos’ meeting time, not any police radio code.
How should I celebrate responsibly?
Keep it 21+, buy from licensed dispensaries, store products safely away from minors, never drive impaired, and look out for the people around you.
Who were the Waldos?
Five friends from San Rafael High School in California, Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz, and Mark Gravich, who nicknamed themselves for the wall they hung out by. They remain credited as the originators of “420.”
Is 4/20 an official holiday?
No, it’s a cultural observance, not a government holiday. But it’s widely recognized, and in legal states it’s become a significant day for the cannabis community and the businesses that serve it.

Celebrate responsibly

However you mark the day, keep it grown-up: 4/20 is for adults 21 and over. Buy from OCM-licensed dispensaries so your products are tested and labeled, store everything
safely away from anyone under 21, never drive impaired, and look out for the people around you. For the official rules, see the NY Office of Cannabis Management. For more on the origin story, Rolling Stone has a great deep dive.
Want to be part of the energy? Browse the Root 9 menu, follow along for our seasonal specials, or stop by Root 9 in Wappingers Falls, our doors are open and our team is ready to help.