Historical timeline of U.S. cannabis

The history of cannabis in the United States is a complex journey shaped by shifting social attitudes, political movements, and evolving laws. From early 20th-century prohibition to the sweeping legalization efforts of the 21st century, cannabis policy has reflected broader debates about medicine, criminal justice, and individual freedom. This timeline traces key moments in U.S. cannabis history—highlighting landmark legislation, court rulings, and cultural turning points that have shaped how the country views and regulates the plant today.

This is a work in progress.

Gov. Greg Abbott vetos bill outlawing hemp-derived THC

Texas - June 22, 2025

Gov. Greg Abbott vetoed a controversial state ban on THC products and soon after called a special legislative session, urging lawmakers to impose strict regulations instead.


Texas legalizes medical use for cannabis

Texas - June 21, 2025

Governor Greg Abbott (R) signed House Bill 46 into law, expanding the state’s limited medical cannabis program, known as the Texas Compassionate Use Program.


U.S. expands cannabis research with passage of medical marijuana research bill

United States - Dec. 2, 2022

The Medical Marijuana and Cannabidiol Research Expansion Act was signed into law, making it easier to conduct medical research on cannabis. It is the first standalone cannabis reform legislation ever enacted at the federal level.


Alabama legalizes medical marijuana

Alabama - May 17, 2021

On May 17, 2021, Governor Kay Ivey signed Senate Bill 46—the Darren Wesley "Ato" Hall Compassion Act—into law, legalizing medical cannabis. The law prohibits sales of raw cannabis and edible products like cookies or candies.


Arizona begins recreational marijuana sales

Arizona - Jan. 22, 2021

The first state-licensed recreational marijuana sales began in Arizona, making it the fastest state in U.S. history to move from voter approval to retail sales.


Arizona voters legalize recreational marijuana

Arizona - Nov. 3, 2020

Arizona Proposition 207, known as the Smart and Safe Arizona Act, passes with 60% of voters approving the measure which legalizes adult recreational use of marijuana.


The 2018 Farm Bill legalizes hemp and hemp-derived products in the U.S.

United States - Dec. 20, 2018

The 2018 Farm Bill, signed into law on December 20, 2018, marked a major shift in U.S. cannabis policy by legalizing industrial hemp at the federal level. For the first time since 1937, hemp—defined as cannabis containing less than 0.3% THC—was removed from the Controlled Substances Act, effectively distinguishing it from marijuana. The bill allowed farmers nationwide to grow and sell hemp commercially, and it opened the door for expanded research, interstate commerce, and crop insurance for hemp producers.


New law prohibits Justice Department from spending funds to interfere with state medical cannabis

United States - Dec. 16, 2014

After six failed attempts, the Rohrabacher-Farr amendment passed the House and became law in December 2014 as part of an omnibus spending bill. Originally introduced by Rep. Maurice Hinchey in 2001, it prohibits the U.S. Department of Justice from using federal funds to interfere with state medical cannabis laws. It marked the first time either chamber of Congress voted to protect medical cannabis patients, representing a historic milestone for federal cannabis reform. However, the amendment does not change the legal status of cannabis and must be renewed each fiscal year to remain in effect.


Alabama approves 'Carly's Law' allowing CBD use for patients

Alabama - April 1, 2014

Governor Robert Bentley signs Carly's Law, permitting the University of Alabama at Birmingham to provide non-psychoactive CBD oil to children with debilitating seizures as a clinical study.


Washington becomes first U.S. state to legalize recreational marijuana use

Washington - Dec. 6, 2012

Washington voters approve Initiative 502 legalizing recreational marijuana for adults 21 and older.


Medical marijuana approved by Arizona voters

Arizona - Nov. 2, 2010

In 2010, Arizona voters approved Proposition 203, legalizing medical marijuana for patients with qualifying conditions.


Alaska voters legalize medical marijuana

Alaska - Nov. 4, 1998

Almost 69% of Alaska voters approve Measure 8, an initiative allowing patients with qualifying conditions to possess and use marijuana with a doctor's approval.


Washington State legalizes medical marijuana

Washington - Nov. 3, 1998

Medical marijuana is legalized after Initiative 692 passes with 59% of the vote.


California becomes first state to legalize medical marijuana

California - Nov. 5, 1996

California voters approved Proposition 215, also known as the Compassionate Use Act, making it the first state in the U.S. to legalize medical marijuana.


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