1915: Utah makes marijuana illegal. It's the second state in the nation (California was first) and the first one bordering Idaho to do so.
1923: Nevada, Oregon and Washington pass laws making marijuana illegal.
1927: Idaho passes a law making marijuana illegal. Nebraska, Kansas and Colorado ban marijuana the same year.
1929: Wyoming bans marijuana, making it now illegal in every state bordering Idaho.
1996: California becomes the first state to legalize medical marijuana.
November 2007: Voters in Hailey approve initiatives to legalize medical marijuana, make enforcement of marijuana laws the lowest police priority and legalize industrial hemp. They rejected one that would have legalized marijuana use and required the city to regulate sales.
Early 2008: Believing the voter initiatives to be illegal, several Hailey officials sue their city.
May 2008: Hailey voters re-pass the same three pro-marijuana initiatives.
2009: Fifth District Judge Robert Elgee guts Hailey's marijuana initiatives.
2010: Hailey adopts a policy saying marijuana use on private property will be the police department's lowest priority.
2012: A proposed initiative to allow medical marijuana in Idaho fails to get enough signatures to make the ballot.
November 2012: Voters in Colorado and Washington become the first to legalize recreational marijuana use.
2013: The Idaho Legislature passes a resolution declaring its opposition to legalizing marijuana in any form. The resolution condemns marijuana legalization in neighboring states and a proposed medical marijuana ballot initiative. A joint memorial calling on the federal government to enforce drug laws in all states fails, though.
November 2014: Voters in Oregon approve legal recreational marijuana, bringing legal marijuana even closer to southern Idaho.
2015: The Idaho Legislature passes a law to allow use of cannabidiol oil, a non-psychoactive extract, to treat severe seizure disorders, not by legalizing it outright but by creating a legal defense for possessing it under some limited circumstances. Gov. C.L. "Butch" Otter vetoes the measure, instead issuing an executive order creating a CBD oil experiment in which a limited number of children can take part.
2015: New Approach Idaho starts to gather signatures for a petition to create a medical marijuana program in Idaho and to decriminalize possession of small amounts of marijuana by adults. Also in 2015, residents of Huntington, Ore., debate whether to allow legal marijuana sales in the city.
March 2016: New Approach withdraws its petition, citing issues with its wording.
2016: Two dispensaries open in Huntington, putting legal marijuana a little more than an hour's drive from the Treasure Valley. Most other cities in eastern Oregon opted not to allow dispensaries. Marijuana is still illegal in Idaho.
Fall 2016: Signature gathering begins for another petition to allow medical marijuana in Idaho.
November 2016: Voters in Nevada approve legal recreational marijuana.
2017: Eight states have legalized recreational marijuana, while a further 10 have "decriminalized" possession of small amounts for recreational use (generally speaking this means it's treated like a traffic ticket rather than a misdemeanor) while also legalizing medical marijuana. Thirteen states have kept recreational marijuana possession as a crime while allowing medical marijuana. Most of the remaining states also allow medical use of cannabidiol oil, even if marijuana is still illegal in other circumstances. Idaho, Kansas and South Dakota are the only states left where possession of marijuana or cannabidiol oil is always illegal. (With the limited exception of the CBD oil experiment authorized by Otter's executive order.)
November 2018: The earliest date when people will be able to apply for licenses to open dispensaries selling recreational marijuana in Elko County, Nev. Up to two dispensaries will be allowed in the county under state law, but municipalities will also be able to decide whether or not to zone to allow marijuana businesses.
SOURCES: Books on the history of drug laws; Idaho legislative records; newspaper and media reports from the Times-News and others; Nevada Department of Taxation.