According to the State of Legal Marijuana Markets Report (4th Edition), published by ArcView Market Research and produced by New Frontier, California is the largest medical marijuana program in the country among states where medical marijuana is currently legal.
The California market is fueled by the state's large size, longevity as the first-in-the-nation medical marijuana program, and low barriers to patient access.
Even with California's newly passed medical marijuana law, which will significantly tighten the program with new restrictions, the market is still projected to reach $2.6 billion in sales in 2020. That is nearly double Colorado's $1.5 billion, and over five times the size of the markets in Arizona, Oregon, and Michigan for that year.
If legalized in 2016, the medical marijuana markets in Ohio and Pennsylvania will become two of the largest in the country by 2020.
According to the data, a handful of states in the western U.S. project to command over 50% of the medical marijuana market by 2020.