Thornton, CO Public Conduct: Public Marijuana Use (2026)

Section 38-297(a) targets consumption that is both openly, meaning unconcealed or obvious, and publicly, meaning in a public place or an outdoor spot clearly observable from one. The city defines public place broadly under subsection (l): parks, playgrounds, parking lots, streets, sidewalks, alleys, and even private property such as apartment common areas, shopping centers, bike paths, and hiking trails whenever the public has an express or implied license to enter, regardless of posted time or conduct restrictions. Subsection (b) separately bars anyone 21 or older from possessing more than one but less than two ounces anywhere in the city except at their primary residence where it was grown, while subsection (c) makes any possession, display, ingestion, or use by a person under 21 unlawful anywhere in Thornton.

Sales, transfers, or purchases outside a licensed marijuana establishment under Section 42-701 are also prohibited under subsections (d) and (e). Officers may rely on the Duquenois-Levine reagent field test or a certified drug recognition expert's qualitative result as prima facie evidence of marijuana under subsection (m). A valid Colorado Department of Public Health and Environment medical marijuana registry card presented at arraignment is an affirmative defense to a possession charge and can result in dismissal under subsection (o).