1923: Some medical marijuana preparations legal under Oregon law.
1935: Oregon adopts Uniform State Narcotic Drug Act, making all cannabis illegal except very small-dose amounts of cannabis extract.
1941: All cannabis illegal in Oregon, including medical.
1973: Oregon first U.S. state to decriminalize marijuana. Possession of up to one ounce results in a fine similar to a traffic violation.
1986: Oregonians vote on Ballot Measure 5, which would legalize private possession and growth of marijuana for personal use. Ballot fails to pass with a vote of 74 percent in favor and 26 percent opposed.
1997: Oregon Legislature tries to recriminalize possession of marijuana, but an opposing petition stops it from going to a public vote.
1998: Ballot Measure 67 legalizes medical marijuana in Oregon with a vote of 55 percent in favor and 45 percent opposed.
2005: Oregon Legislature increases amount of permissible medical marijuana possession per patient from 20 ounces to 24 ounces and 3 mature plants to 6 mature plants.
2009: Board of Pharmacy down-schedules marijuana from Schedule I to Schedule II narcotic.
2012: Measure 80, which would legalize recreational marijuana, fails with a vote of 53 percent opposed and 47 percent in favor.
2014: Measure 91 legalizes possession and growth of recreational marijuana for Oregonians 21 years and older with a vote of 56 percent in favor and 44 percent opposed.
July 1, 2015: Provisions from Measure 91 take effect. Possession of up to one ounce
of recreational marijuana in public and eight ounces at home is legal for people over age 21. Oregonians of age can possess up to four mature plants at home for personal use.
Jan. 1, 2016: Oregon Liquor Control Commission will implement regulations for production, processing and sale of marijuana.