The number did not come from a police radio code. That is the version most people have heard, and it is wrong; it was printed in error and then repeated until it hardened into folklore.

The actual origin is smaller and better. In 1971, five students at San Rafael High School in California, who called themselves the Waldos because they hung around a particular wall, heard about an abandoned cannabis crop and got hold of what was supposedly a map to it. They agreed to meet at the Louis Pasteur statue on the school grounds at 4:20 in the afternoon to go looking. They called the plan "4:20 Louis," then shortened it to 4:20, and it became their private code word.

They never found the crop. The code word outlived the search by half a century.

How five teenagers set a global schedule

The Waldos were Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz and Mark Gravich. What turned their in-joke into an international date on the calendar was proximity to the Grateful Dead: one of them became a roadie for the band's bassist, Phil Lesh, and the term spread through the Dead's touring community. High Times magazine picked it up, first printing it in May 1991, and its editor Steven Hager pushed the Waldos' account as the authentic one after the magazine's own earlier coverage had blamed the police-code myth.

A rival San Rafael group led by Brad Bann has disputed the claim, saying they used it first. Either way it is a local slang term from one California town in the early 1970s, which is a considerably stranger fact than the tidy story about a radio code.

Which brings us to Long Island in 2026

Cannabis history is fun. What actually affects anyone reading this on Long Island is the law, and the law here is recent enough that a lot of people are working from out-of-date assumptions.

New York's Marijuana Regulation and Taxation Act was signed on March 31, 2021, legalizing recreational cannabis for adults 21 and over. It set possession limits of up to three ounces of cannabis flower or up to 24 grams of concentrate on your person. Those are the numbers, and they have not changed since.

What legalization did not do was make every storefront selling cannabis a legal one, and that is where Long Island gets complicated.

The licensed shop question

New York's rollout produced a large gray market of shops that look exactly like dispensaries, in some cases on the same commercial strips as licensed ones, selling product that has not been through the state's testing and labeling requirements. Distinguishing them by appearance is not realistic. Both have signage, both have staff, both take your money.

The state built a specific mechanism for this. Every licensed dispensary must post the Dispensary Verification Tool near its main entrance. It carries a QR code that resolves to the Office of Cannabis Management's own list, so a shop that is legitimately licensed can prove it in about five seconds while you stand in the doorway.

The state also publishes a Buy Legal Map of operating adult-use dispensaries, 703 of them statewide as listed by the Office of Cannabis Management. Checking that map before you drive somewhere is the single most useful thing in this article.

Why there are fewer shops here than you would expect

The Marijuana Regulation and Taxation Act let cities, towns and villages opt out of hosting retail dispensaries and on-site consumption. Long Island is a region of many small municipalities, each with its own board, and a great many of them took that option.

The practical result is a patchwork: a licensed dispensary can be legal on one side of a municipal line and prohibited on the other, and the boundaries do not follow anything a visitor would recognize. This is also why the retail map here changes: opt-out decisions can be revisited, licenses are still being issued, and any specific count of dispensaries goes stale quickly.

Rather than trust a number in an article, including this one, use the state's map. It is maintained by the regulator, and it is the same list the verification QR code points at.

The part people still get wrong

Legal to possess is not legal everywhere, and the distinction catches people out. Cannabis remains federally illegal, which matters at airports, on federal land and for anyone in federally regulated employment. Driving while impaired is a criminal offense regardless of how you obtained the product or how legal the purchase was.

Landlords, employers and schools all set their own rules within what the law allows, and legalization did not override private policies. And the age floor is 21, enforced at the point of sale by shops that risk their license on it.

The honest summary

420 is a piece of American folk history invented by teenagers who were bad at treasure hunting and good at branding without knowing it. It is worth knowing the real story mostly because the fake one is so widely repeated.

The cannabis situation on Long Island is the more consequential subject, and it comes down to one habit: check the state's map or the QR code in the window before you buy. Everything else, the possession limits, the age, the driving rules, is straightforward once you know the shop you are standing in is real.