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Bicycle Day (psychedelic holiday)

Informal annual observance on April 19

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionAug 21, 2026
Entity authoritySource title only
Source-derived summary

Bicycle Day is an unofficial celebration on April 19 of the psychedelic revolution and the first psychedelic trip on LSD by Albert Hofmann in 1943, in tandem with his bicycle ride home from Sandoz Labs. It is commonly celebrated by ingesting psychedelics and riding a bike, sometimes in a parade, and often with psychedelic-themed festivities. The holiday was first named and declared in 1985 by Thomas Roberts, a psychology professor at Northern Illinois University, but has likely been celebrated by psychedelic enthusiasts since the beginning of the psychedelic era, and celebrated in popular culture since at least 2004.

Editorial summary

This brief starts where responsible research should: with the source description of “Bicycle Day (psychedelic holiday)” as informal annual observance on April 19. Everything that follows is an evidence route, not borrowed authority.

Editorial reviewA practical starting point whose main value is the path it opens into stronger specialist and primary sources. The current lead gives the account dated anchors—1943, 1985, 2004—that can be checked directly. The selected authority fields contribute no independent date. The account is most persuasive where Bicycle, psychedelic and holiday can be independently traced.
Editorial analysis

Why this record matters

The subject matters to the general reference register because the source frames it as informal annual observance on April 19. Its deeper value depends on whether names, dates, institutions and citations support that framing.

Evidence profile

The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Aug 21, 2026. The first chronological checks are 1943, 1985 and 2004.

Critical limits

A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.

How to read it

Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.

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  2. Expand the search: follow Bicycle Day (psychedelic holiday) primary sources, Bicycle Day (psychedelic holiday) archive and Bicycle research across catalogues and specialist indexes.
  3. Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.

Questions for further research

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Source & attribution

This entry incorporates text from “Bicycle Day (psychedelic holiday)” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.