Cannabis in Nevada became legal for recreational use effective January 1, 2017, having been legalized by ballot initiative in 2016. Medical marijuana use was legalized by ballot initiative in 2000, and has been available to licensed individuals in the state since shortly after that date. Nevada also licenses growers and distributors, and citizens of Nevada are banned from growing their own cannabis unless they live more than 25 miles from a licensed dispensary.
Nevada first banned cannabis in 1923, during a nationwide trend of states limiting the drug between 1911-1933. 
Medical marijuana (1998, 2000)
Nevada voters approved Question 9 – the Nevada Medical Marijuana Act – in 1998, with 59% of the vote.  It was approved again in 2000, with 65% of the vote.  Because the initiative was a constitutional amendment, it required approval in consecutive elections in order to become law. 
Failed recreational legalization (2002, 2006)
In 2002 "Question 9" went before the voters with a proposal to legalize and regulate recreational cannabis, but was soundly defeated at the polls.  Legalized cannabis appeared on the ballot again in 2006 as the Nevada Regulation of Marijuana Initiative, receiving 44% of the vote. 
Question 2 was a 2016 Nevada voter initiative to legalize cannabis. The official title was "Initiative to Regulate and Tax Marijuana".  The measure, which appeared on the November 8, 2016 ballot, sought to legalize possession of up to one ounce of cannabis for adults over the age of 21.   The initiative did not include provisions for regulation beyond taxation, such as licensing retailers. 
Distribution and Regulation (2017)
On July 1, 2017 Nevada dispensaries began the sale of recreational marijuana.  The new law means anyone over the age of 21 that has a valid photo ID may purchase recreational marijuana in the state of Nevada.