Hempfest, Mile High 420, and the Great Cannabis Gatherings

Last verified: April 2026

Seattle Hempfest — The World’s Largest

Seattle Hempfest was founded in 1991 and grew into what its organizers and many observers call the largest annual cannabis reform rally on earth. At its peak in 2008, attendance was estimated at 310,000 over the three-day weekend. The event has been held at Myrtle Edwards Park on the Seattle waterfront for most of its history, with sound stages, activist speakers, vendor booths, and — famously — open cannabis consumption that law enforcement has generally treated as non-enforcement territory.

Executive Director Vivian McPeak has led Hempfest for decades. McPeak is one of the most recognizable names in American cannabis reform organizing, and his speeches opening the festival each year have become part of the event’s ritual. As of 2026, Hempfest’s long-term future is uncertain — rising city costs, security concerns, and post-legalization cultural shifts have strained the event’s finances. But for three decades, it has been the anchor event of the Pacific Northwest cannabis calendar.

Denver Mile High 420 Festival

The Mile High 420 Festival at Civic Center Park in downtown Denver is the largest April 20 celebration in the United States. Held annually on 4/20, it draws tens of thousands of people for a day of live music, speakers, vendor booths, and cannabis consumption in a public park setting that Denver’s city ordinances have adapted to accommodate.

The event has grown alongside Colorado’s cannabis industry since recreational sales began on January 1, 2014. It now functions as both a cultural celebration and an industry showcase — brands launch new products around the event, dispensaries run their biggest sales of the year, and national media use the festival as the annual visual shorthand for cannabis legalization.

Boston Freedom Rally

The Boston Freedom Rally, organized by MassCann/NORML (the Massachusetts chapter of the National Organization for the Reform of Marijuana Laws), has run continuously for more than 34 years on Boston Common. It is one of the oldest continuously operating cannabis reform rallies in the country.

The Freedom Rally predates Massachusetts’s legalization by decades — it began as an unambiguously political protest rally in the early 1990s and remained one through the long decriminalization fight in the 2000s. Massachusetts legalized medical cannabis in 2012 and adult-use in 2016. The Freedom Rally survived the transition and continues as part protest, part celebration, part culture festival. Speakers have included NORML founders and leaders, and the event has historically been tolerated by Boston police with an understanding that enforcement is light so long as the crowd is peaceful.

San Francisco’s Hippie Hill

Hippie Hill in Golden Gate Park is San Francisco’s unofficial April 20 gathering — and one of the oldest continuous cannabis gatherings in the United States, predating nearly all legal markets. Every April 20, tens of thousands of people gather on the grassy slope near the park’s eastern edge for an open-air cannabis celebration that the city has, over the decades, moved from actively discouraging to pragmatically managing.

In recent years, Hippie Hill has become a permitted event with stages, port-a-potties, licensed vendor areas, and a security perimeter. The shift from unofficial gathering to permitted event has been contentious — some longtime attendees see it as the loss of something genuinely countercultural, others see it as the responsible maturation of a crowd that had outgrown improvisation.

Green Wednesday — The Industry’s Biggest Sales Day

Not a gathering in the traditional sense, but worth noting in any overview of cannabis culture’s big days: Green Wednesday, the Wednesday before Thanksgiving, has quietly become one of the highest-volume sales days of the year for legal cannabis. It’s a cannabis analog to Black Friday, driven by people preparing for family gatherings, travel, and long holiday weekends. See the dedicated page for how to navigate the rush.

Cannabis Cup Events

The Cannabis Cup, originally created by High Times editor Steven Hager in Amsterdam in 1988, is a strain and product competition that now runs in multiple U.S. states. It is less a festival than a contest, but the public events around each Cup — judging, panels, industry parties — have become their own cultural anchor. The Cup has crowned iconic strains from Skunk #1 (the 1988 original winner) to Super Lemon Haze (2008–09). In 2025, High Times hosted its first Cannabis Cup in New York, marking the state’s arrival as a major cannabis market.

MJBizCon — The Industry’s Trade Event

MJBizCon in Las Vegas is the largest cannabis business trade show in the world, drawing 20,000+ attendees and 1,000+ exhibitors annually. It is not a consumer festival — it’s for operators, regulators, investors, and press — but it’s a useful marker of how far the industry has professionalized. A cannabis executive in 2026 attends MJBizCon the way a tech executive attends CES.

The 4/20/2020 Moment

The pandemic reshaped cannabis festival culture in ways worth remembering. April 20, 2020 — the date sometimes called “the most 420 day that ever 420’ed,” because the date contained four twenties (4/20/2020) — was expected to be the biggest cannabis celebration in history. Instead, COVID-19 forced everything virtual.

Denver’s Mile High 420 festival was cancelled. San Francisco Mayor London Breed tweeted a now-famous warning: “To be clear: 4/20 will not be tolerated this year.” Hippie Hill was closed. Seattle Hempfest went virtual. Every major gathering shut down or moved online.

But something important happened at the same time: cannabis dispensaries were designated essential services in most legal states, allowed to remain open through lockdown. Legal cannabis sales surged over 50% in 2020. The designation marked a genuine normalization turning point — cannabis had become infrastructure. The in-person festivals came back in 2021 and 2022, but they came back to a country where cannabis was a more ordinary part of daily life than it had been when they left.

International Gatherings Worth Noting

• Cannabis Cup Amsterdam — the original, still held most years in the Netherlands, the reference point for every other Cup that followed.
• Spannabis (Barcelona, Spain) — Europe’s largest cannabis expo, combining trade show and cultural festival elements.
• Global Marijuana March — held in cities around the world on the first Saturday in May, coordinated reform demonstration rather than consumption event.

How to Think About Festival Etiquette

Every festival has its own rules and its own tolerance levels. A permitted event with licensed vendors operates under a different set of norms than an unpermitted gathering at a park. The default etiquette for any cannabis festival: bring your own supply or buy from licensed vendors (not random parking-lot dealers), share within your own group, be courteous to non-consuming attendees and staff, and don’t leave trash in the space.

For 4/20 specifically, the how to celebrate page covers the full range of options from festival-scale to low-key-at-home. For the history behind the date itself, start with what is 420.