The history behind 4/20

Randi Mattox

Although Congress hasn’t declared it a national holiday yet, April 20 has become accepted as the day in which people celebrate marijuana. As a result, the term “4/20-ing” has become synonymous with “smoking weed” and 4:20 p.m. has become a popular time of day to engage in the consumption of cannabis. But where did all of this start?



There are countless origin stories of 4/20 and multiple people that claim they were the first to use the term. Perhaps the most common origin story is that 420 was used as a police radio code to reference smoking in progressIn fact, that was the exact answer that Warren Haynes of the Allman Brothers Band told the Huffington Post when they asked him where the phrase originated. It seems like a logical origin. But unfortunately, this theory has no merit. Currently, 420 is the police radio code for absolutely nothing.

Hitler’s birthday

Another commonly-told origin story is that the term refers to Adolph Hitler’s birthday. But I think it’s safe to say that a bunch of happy hippies who smoked a lot of weed did not decide on the term because it coincided with the birthday of someone who killed 6 million people. 

The Grateful Dead

The Grateful Dead is also frequently accredited with creating the term. This theory claims that the Grateful Dead members always requested room 420 when they stayed in hotels. In this case, it is highly implausible that one would be able to find a hotel with an available room 420 whenever they needed it. However, the Grateful Dead does get some credit for popularizing the culture of 4/20.

High school students

The term also does not refer to the number of chemical compounds in cannabis, the date of Janis Joplin’s death, the California penal code or a math equation that uses numbers from Bob Dylan songs. The actual origin story has nothing to do with popular culture, science or the law. The real origin story of 4/20, and the only one that can be proveninvolves a group of high school students at San Rafael High School in California called the Waldos.  

The story begins in 1971 when a U.S. Coast Guardsman became worried that he would get in trouble for growing marijuana. The guardsman decided to stop growing his plants and gave a map to his brother that described the location of his harvest.  

The guardsman’s brother showed it to his group of friends at school called the Waldos, named after their tendency to hang out by a wall, and they all agreed to meet at the statue of Louis Pasteur on San Rafael High School’s campus at 4:20 p.m. to search for the marijuana plants. 

Photo Courtesy:
(Photo Courtesy:

They never found the harvest, but the Waldos began saying “420 Louie” when referencing their search. As time passed, they dropped “Louie” and just said “420.” And as more time passed, they simply used the term “4/20” to secretly talk about weed.  


After the Waldos began using the term regularly, it spread rather quickly. The Waldos had a lot of contact with people who smoked weed because one of their dads was in a popular Grateful Dead cover band. The same people that attended the cover band’s concerts also attended Grateful Dead concerts and were acquaintances with other people that attended Grateful Dead concerts. Concert after concert, 4/20 was used in conversation. And knowing that the Grateful Dead had arguably the largest following of any band during the 1970s, you can see how the term made its way into mainstream vocabulary.

The most convincing part of the Waldos’ origin story is that they have documented proof. The Waldos have letters that date back to the early 1970s in which the term is used to reference weed and a flag that one of their friends (not a member of the Waldos) made to commemorate the term that features the number 420 and a marijuana leaf. Both the letters and the flag are proven to be the earliest documentations of the use of the term 4/20 and are sealed in a vault that is rarely available for inspection.  

Yes. You read all of that correctly. A small group of weed-loving high school students in the 1970s coined the term that is now used worldwide. Whether you’re completely loathing the fact that you will be in Colorado on April 20 or you plan to join in on this year’s 4/20 festivities, you have the Waldos to thank for the fact that our world dedicates a day to marijuana.

Go to to learn more about the Waldos and to view pictures of the documents.

Collegian Reporter Randi Mattox can be reached at or on Twitter @randimattox.