Number referring to cannabis
420, 4:20, or 4/20 (pronounced four-twenty) is cannabis culture slang for marijuana and hashish consumption, especially smoking around the time 4:20 p.m., and also refers to cannabis-oriented celebrations that take place annually on April 20 (which is 4/20 in U.S. form).  At locations in the United States where cannabis is legal,  cannabis dispensaries will often offer discounts on their products on April 20.
In 1971, five high school students in
San Rafael, California,  used the term "4:20" in connection with a plan to search for an abandoned cannabis crop, based on a  treasure map made by the grower.  Calling themselves the Waldos,   because their typical hang-out spot "was a wall outside the school",  the five students—Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz, and Mark Gravich  —designated the  Louis Pasteur statue on the grounds of  San Rafael High School as their meeting place, and 4:20 pm as their meeting time. The Waldos referred to this plan with the phrase "4:20 Louis". After several failed attempts to find the crop, the group eventually shortened their phrase to "4:20", which ultimately evolved into a code-word the teens used to refer to consuming cannabis. 
Steven Hager of popularized the story of the Waldos. High Times The first  High Times mention of 4:20 smoking and a 4/20 holiday appeared in May 1991, and the connection to the Waldos appeared in December 1998. Hager attributed the early spread of the phrase to  Grateful Dead followers —after "Waldo" Reddix became a roadie for the  Grateful Dead's bassist, Phil Lesh —and called for 4:20 pm to be the socially accepted time of the day to consume cannabis. 
International day for cannabis-related protests and events
Vancouver, April 20, 2012
April 20 has become an international
counterculture holiday, where people gather to celebrate and consume cannabis.   Many such events advocate for the  liberalization and legalization of cannabis. Vivian McPeak, a founder of Seattle's Hempfest states that 4/20 is "half celebration and half call to action". Paul Birch calls it a global movement and suggests that one cannot stop events like these. 
On that day many marijuana users protest in
civil disobedience by gathering in public to smoke at 4:20 pm.
As marijuana continues to be decriminalized and legalized around the world,
Steve DeAngelo, cannabis activist and founder of California's Harborside Health Center, notes that "even if our activist work were complete, 420 morphs from a statement of conscience to a celebration of acceptance, a celebration of victory, a celebration of our amazing connection with this plant" and that he thinks that "it will always be worthy of celebration".  
In North America
North American observances have been held at many locations, including:
Australian observances have been held at many locations, over many years, including:
Events have also been held in
Hyde Park in London and  Dunedin, New Zealand, at the University of Otago.     
Ljubljana, Slovenia, the University of Ljubljana's student organization has carried out several annual cannabis-themed protests that have contributed to the debate on cannabis status in Slovenia and the subsequent legislation proposals in 2018 by gathering responses from various political parties in Slovenia and ranking them accordingly. 
Northern Cyprus, known for strict drug laws and intolerance to cannabis consumption, the first 420 event was held in the capital city  Lefkoşa in 2015. On April 20, 2017, a small group of protesters carried out an event near the parliament building and made a public statement, demanding the legalization of cannabis sale, consumption, and production with state regulations.
Despite two studies reporting a supposed increase in the risk of
fatal motor vehicle crashes on April 20,  further investigation and analysis found the evidence did not support such claims.    
In the USA, signs bearing the number 420 have been frequently stolen. In Colorado, the
Colorado Department of Transportation replaced the Mile Marker 420 sign on I-70 east of Denver with one reading 419.99 in an attempt to stop the thievery; however, the folklore of the 419.99 sign has caused it to be stolen, too, as well as becoming a tourist destination. As of August 2018, the sign was missing, presumed stolen.  The Colorado DOT usually will not replace signs that are repeatedly taken, but began the practice of replacing further down the road after "  69" mile marker signs were frequently stolen—these were replaced with "68.5 mile" ones. The  Idaho Department of Transportation (ITD) replaced the mile marker 420 sign on U.S. Highway 95, just south of Coeur d'Alene, with mile marker 419.9. The Washington State Department of Transportation (WSDOT) implemented similar measures,  but only replaced one of the two 420 signs in the state, with the remaining one being subsequently stolen.  According to  , there are eleven 420 mile markers in the US, after three replacements and one stolen and not replaced. The Washington Post In  Goodhue County, Minnesota, officials have changed "420 St" street signs to "42x St". The mile marker 420 sign on  U.S. Route 89, the only 420 marker in the state of Utah, is frequently stolen.
This behaviour has not been observed in countries such as
Australia, the Netherlands [ and nl] the UK which also have roads numbered 420.
Legislation and other government recognition
California Senate Bill 420 was introduced to regulate medical marijuana use, in deliberate reference [ to the status of 420 in marijuana culture. An unsuccessful 2010 bill to legalize ] citation needed cannabis in Guam was called Bill 420. A North Dakota bill to legalize cannabis was HB 1420, introduced in January 2021. 
The Marijuana Freedom and Opportunity Act (which if enacted would
decriminalize and deschedule cannabis in the United States) was announced by Senator and Senate Minority Leader Chuck Schumer (D-New York) on April 20, 2018.  On January 9, 2019, H.R. 420 was introduced into the  116th Congress by Representative Earl Blumenauer (D-Oregon), named the Regulate Marijuana Like Alcohol Act, which is designed to remove cannabis from the Controlled Substances Act and return regulation to the states.
The State of Colorado auctioned off several cannabis-themed personalized license plates in 2021, with the bidding to be closed on April 20 (4/20). The highest bid shortly before the auction closed was over $6,500 for "ISIT420".
Following the success of Washington, D.C.'s
Initiative 71 to legalize cannabis in 2014, Mayor Muriel Bowser granted license plate number 420 to the campaign's leader, Adam Eidinger.
books about cannabis have "420" in the title, including the cannabis cookbooks The 420 Cannabis Cookbook, published by Simon & Schuster, and  The 420 Gourmet published in 2016 by HarperCollins. 
"Daily Independent Journal from San Rafael, California". November 20, 1954 . Retrieved . April 22, 2017
Chronicle, San Francisco (1962). . McGraw-Hill The San Francisco Chronicle Reader . Retrieved . April 22, 2017
^ a b
King, Matt (April 24, 2007). "Thousands at UCSC burn one to mark cannabis holiday". . Archived from Santa Cruz Sentinel the original on April 26, 2007.
McCoy, Terrence (April 18, 2014). "The strange story of how the pot holiday '4/20' got its name". The Washington Post . Retrieved . April 18, 2020
"4/20 deals: These Massachusetts cannabis dispensaries are celebrating with events, specials and more". MassLive.com. April 17, 2021.
"Stoner Chic Traces Origin To San Rafael – Snickering high schoolers brought '420' into lexicon". . April 20, 2000 San Francisco Chronicle . Retrieved . April 4, 2012
^ a b
McKinley, Jesse (April 19, 2009). "Marijuana Advocates Point to Signs of Change". The New York Times. Archived from the original on December 18, 2010 . Retrieved . January 23, 2011 Mr. Hager said the significance of April 20 dates to a ritual begun in the early 1970s in which a group of Northern California teenagers smoked cannabis every day at 4:20 pm. Word of the ritual spread and expanded to a yearly event in various places. Soon, cannabis aficionados were using "420" as a code for smoking and using it as a sign-off on flyers for concerts where the drug would be plentiful. In recent years, the April 20 events have become so widespread that several colleges have discouraged students from participating.
^ a b
Grim, Ryan (April 20, 2010). "420 Meaning: The True Story Of How April 20 Became 'Weed Day'. " The Huffington Post . Retrieved . January 23, 2011
Alyssa Pereira (April 20, 2016). "Local originators of term 420 solve 45-year-old mystery". San Francisco Chronicle.
High Times (2012). . Chronicle Books. pp. 97–. The Official High Times Cannabis Cookbook: More Than 50 Irresistible Recipes That Will Get You High ISBN 978-1-4521-0133-0 . Retrieved . April 19, 2012
"High Expectations: Marketers Hope for Buzz on 4/20". The Wall Street Journal. April 20, 2012.
^ a b
Grim, Ryan (April 20, 2009). "What 420 Means: The True Story Behind Stoners' Favorite Number". . Archived from The Huffington Post the original on January 30, 2014 . Retrieved . January 23, 2011
^ a b
Olivia B. Waxman (April 19, 2017). "What the Guys Who Coined '420' Think About Their Place in Marijuana History". Time. Archived from the original on April 20, 2017 . Retrieved . April 20, 2017
^ Statue by
Beniamino Bufano, "Louis Pasteur – 1940". New Deal Art Registry . Retrieved . November 16, 2018
Edison, Mike (2009). . Faber & Faber. pp. 207–. I Have Fun Everywhere I Go: Savage Tales of Pot, Porn, Punk Rock, Pro Wrestling, Talking Apes, Evil Bosses, Dirty Blues, American Heroes, and the Most Notorious Magazines in the World ISBN 978-0-86547-903-6 . Retrieved . April 20, 2013
"Wake 'n' Bake!" erroneously attributes the origin of the term to a police code
^ a b
"Stoner Smart, or Stoner Stupid?". High Times. August 2002. Archived from the original on May 14, 2012 . Retrieved . April 20, 2012
Halnon, Karen Bettez (April 11, 2005). "The power of 420". Archived from the original on May 13, 2013.
"420 event lists".
"How marijuana's high holiday came to be". New York Post. April 20, 2017 . Retrieved . April 22, 2017
Gayle, Damien (April 19, 2015). "Thousands of cannabis users roll up in Hyde Park for annual 4/20 event". The Guardian. Archived from the original on February 27, 2017 . Retrieved . April 22, 2017
"Marijuana's big day is here: '420' celebrations ready to roll". USA Today . Retrieved . April 22, 2017
"Does 4/20 Still Matter?". Rolling Stone . Retrieved . April 22, 2017
"Annual 420 pot rally will be more celebration than protest: Organizers". Toronto Sun . Retrieved . April 22, 2017
Davies, Pete (April 21, 2010). "Washington Square Gets Its Grit Back on 420 Day". Curbed NY . Retrieved . January 7, 2018
Reed, Matt (April 20, 2018), Boston celebrates 4/20 , retrieved April 20, 2021
"A Huge Turn Out for 420 Day on Hippie Hill in San Francisco's Golden Gate Park " San Francisco Citizen". Sfcitizen.com. April 20, 2010. Archived from the original on April 30, 2011 . Retrieved . April 20, 2011
"Students mark 420 at UC Santa Cruz". Santa Cruz Sentinel. April 21, 2019 . Retrieved . April 21, 2020
Amanda del Castillo (April 20, 2019). "Pot enthusiasts in Santa Cruz prepare for 4/20 toker tradition". ABC7 San Francisco . Retrieved . April 23, 2020
Stein, Perry (April 20, 2015). "D.C. residents and activists light up on the National Mall for 4/20". The Washington Post . Retrieved . April 20, 2022
Estepa, Jessica (April 19, 2017). "D.C. activists to hand out joints near U.S. Capitol on 4/20". USA Today . Retrieved . April 20, 2022
"Marijuana protest planned for the Vancouver Art Gallery despite 4/20 moving to Sunset Beach". April 19, 2016.
Hall, Neal (May 2, 2009). "Thousands of marijuana smokers gather in Vancouver to celebrate "420". " . Archived from The Vancouver Sun the original on September 10, 2014 . Retrieved . September 30, 2009
Johnson, Lisa (April 20, 2016). "4/20 pot rally draws tens of thousands in Vancouver". CBC News . Retrieved . April 20, 2016
"420 Day – Cannabis Festival". samesun.com Samesun Nation Travel Blog. Archived from the original on October 22, 2014 . Retrieved . April 20, 2011
"Canada's marijuana activists unite against American-style drug laws – 420 vote mobs to be held in over 10 cities across Canada on April 20th". newswire.ca CNW Group. Archived from the original on September 7, 2012 . Retrieved . April 20, 2011
"Denver's new Mile High 420 Festival announces all-star lineup " Denver Post". denverpost.com. March 8, 2018. Archived from the original on November 20, 2018 . Retrieved . March 14, 2018
"Pot activists to light up on Hill". Cnews.canoe.ca. Archived from the original on July 12, 2012 . Retrieved . April 20, 2011
"Ottawa's Parliament Hill just one site for planned 4/20 protest". Digitaljournal.com. April 11, 2010. Archived from the original on May 11, 2011 . Retrieved . April 20, 2011
"Hundreds of Tokers Flood Alberta Legislature in Protest to Push for Legalization of Marijuana". April 21, 2013 . Retrieved . April 22, 2013
CU's 4/20 pot smoke-out draws crowd of 10,000 : CU News.
"Medical marijuana expected to give momentum to CU-Boulder 4/20 event – Boulder Daily Camera". Dailycamera.com. April 9, 2010. Archived from the original on April 30, 2011 . Retrieved . April 20, 2011
Johnson, Gene. "How 4/20 ... grew ... into a 'holiday'. " chicagotribune.com . Retrieved . April 22, 2017
"Denver 420 event will be a mix of marijuana politics and celebration". April 19, 2017 . Retrieved . April 22, 2017
"4/20 celebrations take place at Nathan Phillips Square without permit". April 20, 2018 . Retrieved . April 20, 2020
"Thousands expected to attend Toronto 4/20 marijuana rally at Yonge-Dundas Square". April 20, 2017 . Retrieved . April 20, 2020
"Photos: 100s turn up, chill out for 420 day on Cal campus". April 21, 2016 . Retrieved . October 22, 2020
"#Plantón420 Has Been Camping Outside the Mexican Senate For a Month". March 6, 2020.
"A Giant Cannabis Plant Was Put Up At Martin Place Overnight, Here's Why". 10 daily. April 19, 2019 . Retrieved . October 23, 2019
"Thousands gather for 'Weed Day' in Melbourne". The Sydney Morning Herald . Retrieved . October 23, 2019
Dopamine (April 19, 2018). "Artists hide 'cannabis plants' around Sydney CBD for 420 protest". Dopamine . Retrieved . October 23, 2019
Connellan, Shannon (April 20, 2018). "Marijuana plants hidden in plain sight for 4/20 stunt". Mashable . Retrieved . October 23, 2019
"Happy 4/20: Activists Have Hidden Weed Plants All Around Sydney". Junkee. April 20, 2018 . Retrieved . October 23, 2019
"These two weapons covered Sydney in 'cannabis plants' to celebrate 4/20". Beat Magazine. April 20, 2018 . Retrieved . October 23, 2019
"Some Blaze Lord Put A Hydroponic Weed Pop-Up In Sydney's Kings X For 4/20". Pedestrian TV. April 20, 2017 . Retrieved . October 23, 2019
"A Public Cannabis Nursery Appears in Kings Cross". Broadsheet . Retrieved . October 23, 2019
Gayle, Damien (April 21, 2016). "Police make 20 arrests at cannabis picnic in London's Hyde Park". the Guardian . Retrieved . May 5, 2016
Porteous, Debbie (June 12, 2008). "Police swoop on cannabis protest". Otago Daily Times . Retrieved . March 31, 2009
"420 Protest". Channel 9 News Dunedin. February 22, 2008. Archived from the original on October 22, 2008 . Retrieved . October 7, 2008
Porteous, Debbie (July 11, 2008). "Campus arrests follow marijuana complaints (+ video)". Otago Daily Times . Retrieved . April 22, 2009
Rudd, Allison (September 26, 2008). "Moore's appeal rejected". Otago Daily Times . Retrieved . April 22, 2009
Rudd, Allison (July 22, 2008). "Lack of quorum foils cannabis vote". Otago Daily Times . Retrieved . April 22, 2009
Rudd, Allison (September 20, 2008). "OUSA general meeting promises controversy". Otago Daily Times . Retrieved . April 22, 2009
"Politični Semafor". marihuanamars. March 20, 2018. Archived from the original on September 26, 2020 . Retrieved . February 3, 2018
Ma, Al (February 2, 2018). "Bo konoplja kmalu legalizirana?". RTVSLO . Retrieved . February 3, 2018
"İşte KKTC'nin uyuşturucu raporu". detaykibris. June 29, 2015 . Retrieved . April 19, 2019
"Meclis önünde 'Elini Otumdan Çek' eylemi". yeniduzen. April 20, 2017 . Retrieved . April 13, 2019
Staples, John A.; Redelmeier, Donald A. (2018). "The April 20 Cannabis Celebration and Fatal Traffic Crashes in the United States". . JAMA Internal Medicine 178 (4): 569–572. doi: 10.1001/jamainternmed.2017.8298. PMC . 5876802 PMID 29435568.
Vandoros, Sotiris; Kawachi, Ichiro (July 2019). "The relative risk of motor vehicle collision on cannabis celebration day in Great Britain" (PDF). Accident Analysis & Prevention. 128: 248–252. doi: 10.1016/j.aap.2019.02.013. PMID 30902341. S2CID 85457198.
Harper, Sam; Palayew, Adam (January 29, 2019). "The annual cannabis holiday and fatal traffic crashes". Injury Prevention. 25 (5): 433–437. doi: 10.1136/injuryprev-2018-043068. ISSN 1353-8047. PMID 30696698. S2CID 59413349.
Aydelotte, Jayson D.; Mardock, Alexandra L.; Teixeira, Pedro G.; Brown, Lawrence H. (November 1, 2018). "Re-examining the Association Between '4/20' and Fatal Crashes—Doobie-ous Data?". JAMA Internal Medicine. 178 (11): 1565. doi: 10.1001/jamainternmed.2018.5856. PMID 30398555. S2CID 53223889.
Staples, John A.; Redelmeier, Donald A. (March 1, 2019). "Association Between April 20 Cannabis Celebration and Fatal Crashes". JAMA Internal Medicine. 179 (3): 456. doi: 10.1001/jamainternmed.2018.8094. PMID 30715145. S2CID 73432259.
Staples, John A; Redelmeier, Donald A (October 2019). "Crashes on cannabis celebration day". Injury Prevention. 25 (5): 476–477. doi: 10.1136/injuryprev-2019-043262. PMID 31302609. S2CID 196618121.
"State alters 420 MM sign to thwart thieves". USA Today . Retrieved . April 18, 2018
"Stratton, Colorado: 419.99 Mile Marker". Atlas Obscura . Retrieved . April 20, 2019
^ a b
Keyser, Hannah (August 20, 2015). "Stoners Keep Stealing 420 Mile Markers, So Some States Have Replaced Them With 419.9". Mental Floss . Retrieved . April 20, 2019
"Idaho replaces mile marker 420 with 419.9 to thwart stoners". . Archived from KTVB the original on August 20, 2015 . Retrieved . August 18, 2015
Jacobs, Julia (January 12, 2019). "Washington State Wants to Stop Theft of Mile 420 Signs. Its Solution? Mile 419.9". The New York Times. ISSN 0362-4331 . Retrieved . January 13, 2019
Ingraham, Christopher (August 20, 2015). "A map of the remaining 420-mile markers in the U.S." Washington Post . Retrieved . April 20, 2019
"County finds fix for missing 420 signs". . Archived from Post-Bulletin the original on April 30, 2017 . Retrieved . July 20, 2015
Kelly Keiter (August 26, 2015). "Officials say theft of '420' road signs no laughing matter". Salt Lake City: KSTU.
Only one shows up for pot bill (July 15, 2010). "Only one shows up for pot bill". Mvguam.com. Archived from the original on July 15, 2015 . Retrieved . July 15, 2015
"Bill Actions for HB 1420". nd.gov official portal for North Dakota government. North Dakota legislative branch . Retrieved . April 20, 2021
Guild, Blair (April 20, 2018). "On 4/20, Sen. Schumer introduces bill to decriminalize marijuana". CBS News . Retrieved . April 19, 2019
Gstalter, Morgan (June 28, 2018). "Schumer unveils bill to decriminalize marijuana". The Hill . Retrieved . April 19, 2019
Tom Angell (January 9, 2019). "New Congressional Marijuana Bill Is Actually Numbered H.R. 420". Marijuana Moment – via Forbes.
, Associated Press, April 13, 2021 Colorado to auction off cannabis-themed license plates
"D.C. mayor offers pot activist Tag 420 for his efforts". Washington Post.
Maggie GRISWOLD (April 14, 2020). "The Best 4/20 Cookbooks for When You Have a Case of the Munchies". Stylecaster. SHE Media.
Naima Karp; Destynee Powell (November 8, 2018), "Celebrate the High Holy Day With These Celebrated Marijuana Cookbooks", spy.com, Penske Media
Jonathan Segura (May 17, 2016), , Cookbooks Previews: June 2016 Publishers Weekly
Look up in Wiktionary, the free dictionary. 420
Holidays, observances, and celebrations in the United States
January January–February February American Heart Month Black History Month
Birthday of Luis Muñoz Marín (PR)
Charles Darwin Day / Darwin Day (CA, DE)
Day of Remembrance (CA, OR, WA, cultural)
Georgia Day (GA)
Lincoln's Birthday (CA, CT, IL, IN, MO, NY, WV)
National Girls and Women in Sports Day
National Freedom Day (36)
Nirvana Day (religious)
Presentation of Our Lord to the Temple (religious)
Promised Reformer Day (religious)
Ronald Reagan Day (CA)
Rosa Parks Day (CA, MO)
Saviours' Day (religious)
Susan B. Anthony Day (CA, FL, NY, WI, WV, proposed federal) Tu B’shvat (religious) February–March March Irish-American Heritage Month Colon Cancer Awareness Month Women's History Month
Annunciation of the Virgin Mary / Annunciation of the Theotokos (religious)
Casimir Pulaski Day (IL)
Cesar Chavez Day (CA, CO, TX, proposed federal)
Emancipation Day in Puerto Rico (PR, cultural)
Evacuation Day (Suffolk County, MA)
Harriet Tubman Day (NY)
Hola Mohalla (religious)
Holi (NY, religious)
L. Ron Hubbard’s Birthday (religious)
Lailat al-Mi'raj (religious)
Liberation and Freedom Day (Charlottesville, VA, cultural)
Mardi Gras (AL (in two counties), LA)
Maryland Day (MD)
National Poison Prevention Week (week)
Nowruz (cultural, religious)
Prince Jonah Kūhiō Kalanianaʻole Day (HI)
Promised Messiah Day (religious)
Saint Joseph's Day (religious)
Seward's Day (AK)
Texas Independence Day (TX)
Town Meeting Day (VT) Transfer Day (VI) March–April
Good Friday (CT, NC, PR, NJ, VI, religious)
Hanuman Jayanti (religious)
Holy Thursday (PR, VI, religious)
Holy Week (PR, religious, week)
Lazarus Saturday (religious)
Mahavir Janma Kalyanak (religious)
Mesha Sankranti / Hindu New Year (religious)
Palm Sunday (PR, religious)
Easter Monday / Bright Monday (VI religious)
Ramnavami (religious) Chandramana Yugadi / Souramana Yugadi (religious) April Confederate History Month May Asian Pacific American Heritage Month Jewish American Heritage Month June Lesbian, Gay, Bisexual and Transgender Pride Month July July–August August September Prostate Cancer Awareness Month Childhood Cancer Awareness Month September–October Hispanic Heritage Month October Breast Cancer Awareness Month Disability Employment Awareness Month Italian-American Heritage and Culture Month Filipino American History Month LGBT History Month October–November November Native American Indian Heritage Month
Ascension of ‘Abdu’l Baha (religious)
All Saints' Day (religious)
Beginning of the Nativity Fast (religious)
Beltane / Samhain (religious)
Barack Obama Day in Alabama (Perry County, AL)
D. Hamilton Jackson Day (VI)
Day after Thanksgiving (24)
Day of the Covenant (religious)
Discovery of Puerto Rico Day (PR)
Election Day (CA, DE, HI, KY, MT, NJ, NY, OH, PR, VA, WV, proposed federal)
Family Day (NV)
Guru Nanak Gurpurab (religious)
Lā Kūʻokoʻa (HI, unofficial, cultural)
Martyrdom of Guru Tegh Bahadur (religious)
Native American Heritage Day (MD, WA, cultural)
Presentation of the Theotokos to the Temple (religious) Unthanksgiving Day (cultural) December
Advent Sunday (religious)
Alabama Day (AL)
Birthday of Guru Gobind Singh Sahib (religious)
Bodhi Day (religious)
Christmas Eve (KY, NC, SC, PR, VI)
Day after Christmas (KY, NC, SC, TX, VI)
Hanukkah (religious, week)
Immaculate Conception (religious)
Indiana Day (IN)
Kwanzaa (cultural, week)
Milad Syedna Mohammed Burhanuddin (religious)
National Pearl Harbor Remembrance Day (36)
Nativity of Jesus (religious)
Old Year's Night (VI)
Pan American Aviation Day (36)
Pancha Ganapati (religious, week)
Rosa Parks Day (OH, OR)
Solemnity of Mary, Mother of God (religious)
Wright Brothers Day (36)
Yule (religious) Zartosht No-Diso (religious) Varies (year round)