420 (Four-Twenty)

420 is an international cultural phenomenon and counterculture holiday centered around the consumption and celebration of cannabis, and it is observed on April 20. What began as a secret code among a small group of high school students has evolved into a global event involving massive festivals, political rallies for legalization, and social gatherings.

See also: National Hemp Day, International Hemp Day

History of 420

The true origin of 420 traces back to San Rafael, California, in 1971. A group of five high school students known as “the Waldos” (because they hung out by a wall) used the term “420 Louis” as a code for their plan to meet at 4:20 p.m. by the statue of Louis Pasteur to search for an abandoned cannabis crop. While they never found the patch, the code stuck as a general shorthand for consuming cannabis.

The term transitioned from a local secret to a global standard thanks to the Grateful Dead. The Waldos had social ties to the band, and the phrase began circulating within the “Deadhead” community. In 1990, a group of fans distributed flyers at a concert in Oakland that explained the “history” of 420. One of these flyers reached Steve Bloom, a reporter for High Times magazine. The magazine began using the term frequently, effectively cementing April 20 as the unofficial worldwide holiday for cannabis culture.

Why is 420 important?

This day is significant because it serves as a yearly barometer for the legalization and decriminalization movement. What was once a day of quiet rebellion is now a major commercial and political event. In regions where cannabis is legal, 420 is a major economic driver for the retail industry. In areas where it remains prohibited, the day is used for organized protests and “smoke-ins” to advocate for civil liberties and the end of the War on Drugs.

The observance also fosters a sense of community and shared identity. It provides a platform for education regarding the medicinal benefits of the plant and the history of its industrial uses (hemp). Furthermore, 420 has influenced mainstream pop culture, appearing in films, music, and literature, and has prompted serious discussions regarding social justice, specifically the disproportionate impact of cannabis prohibition on marginalized communities.

• It marks a day of advocacy for cannabis policy reform and social justice.
• The day celebrates the cultural and artistic contributions of the cannabis community.
• It provides an opportunity for education on the medicinal applications of THC and CBD.
• For legal markets, it is one of the highest-revenue days for small businesses and dispensaries.
• It commemorates the “Waldos” and the grassroots evolution of modern slang.

How to Observe 420

Observation of 420 varies wildly depending on local laws and personal preferences. In many major cities, thousands of people gather in public parks—such as Hippie Hill in San Francisco or Civic Center Park in Denver—to celebrate at exactly 4:20 p.m. Many participants observe the day by supporting local dispensaries, many of which offer “420 deals” and educational pop-up events.

For others, the day is spent at home watching “stoner cinema” classics, listening to psychedelic music, or preparing infused meals. Advocacy is also a major component; many people use the date to contact their representatives about marijuana reform or to donate to organizations like NORML or the Last Prisoner Project, which works to free those still incarcerated for cannabis-related offenses.

• Attend a local festival or concert celebrating cannabis culture.
• Support small businesses and “mom-and-pop” dispensaries.
• Educate yourself on the difference between various strains and their effects.
• Engage in political activism by supporting decriminalization efforts.
• Host a movie marathon featuring films like The Big Lebowski or Pineapple Express.

420 Dates Table