'High Holiday' 420 has hazy origins

Though there are many urban legends out there, the origins of 4/20 as an international holiday to smoke marijuana are hazy.

A farmer puts his marijuana plant into soil
April 20, or 4/20, may be the unofficial holiday for pot smokers, but its origins are particularly hazy.
(Image credit: Eric Limon/Shutterstock)

Today is April 20 — or 4/20 for all the marijuana enthusiasts out there. It is the unofficial holiday for people who want to get high all over the world.

The day has become so inextricably linked with the herbal leaf that a Google search lists 420 as simply one of the date's holidays and observances (along with UN Chinese Language Day). But how exactly did the association between 420 and marijuana begin?

Tia Ghose
Editor-in-Chief (Premium)

Tia is the editor-in-chief (premium) and was formerly managing editor and senior writer for Live Science. Her work has appeared in Scientific American, Wired.com, Science News and other outlets. She holds a master's degree in bioengineering from the University of Washington, a graduate certificate in science writing from UC Santa Cruz and a bachelor's degree in mechanical engineering from the University of Texas at Austin. Tia was part of a team at the Milwaukee Journal Sentinel that published the Empty Cradles series on preterm births, which won multiple awards, including the 2012 Casey Medal for Meritorious Journalism.