Three other states had marijuana-related measures on their ballots. North Dakota voters decided recreational pot wasn't for them , while voters in Missouri passed one of three unrelated measures to legalize medical marijuana. Utah voters also were considering whether to allow medical marijuana and to join the 31 other states that have already done so.
Including Michigan, 10 states and the District of Columbia have legalized recreational marijuana. And Canada recently did so. But the passage in Michigan gives it a foothold in Middle America and could cause tension with neighboring Indiana and Ohio, which overwhelmingly rejected a 2015 legalization measure.
"Troopers that work along the state line are very cognizant of what's going on up north," said Indiana State Police Sgt. Ron Galaviz, a spokesman for the agency's Fort Wayne Post, which stretches north to the Michigan line.
He said if the referendum passed, "we know some of our citizens are going to go over to Michigan to partake." And those who return either under the influence or in possession of pot may learn the hard way that it remains illegal in Indiana.
"We'll enforce our laws as written," added Galaviz, a Michigan native. "If you're traveling to or through our state, we really don't want you bringing it down here."
Kristin Schrader, 51, a Democrat from Superior Township in Washtenaw County, said she voted to legalize marijuana because she doesn't want people leaving Michigan to get it.
"I've got no attachment to marijuana myself, but I don't care to stand in the way of the train while it's coming down the tracks. I don't want people to go to other states to get it and spend their money somewhere else. If there's going to be an economic benefit to legalize marijuana, I want it to be in Michigan."
The Michigan law will take effect in about a month, as the election first has to be certified by the Board of State Canvassers. Ten days after that certification, people age 21 or older will be allowed to have, use and grow the drug, but the process of establishing regulations for its retail sale could take about two years.
The measure, which was endorsed by a national organization of black-owned businesses and a group of retired Michigan law enforcement officers, will create a state licensing system for marijuana businesses and allow cities and townships to restrict them. Supporters say it will raise roughly $130 million in additional tax revenue each year that will go toward road repairs, schools and local governments. They also say it will allow for greater regulation of pot usage and for the police to focus on more pressing problems.
Opponents, including many law enforcement agencies, prosecutors, chambers of commerce and religious groups, said legalizing marijuana would lead to increased use by children, drug abuse and car crashes. They also said Michigan's proposal would be too permissive by allowing people to have up to 2.5 ounces (71 grams) of the drug on them and up to 10 ounces (284 grams) at home.
Unlike Michigan's measure, North Dakota's rejected measure didn't receive any significant funding from outside groups. It came as the state was still setting up its medical marijuana system, which voters approved by a wide margin two years ago.
In Missouri, voters passed one of three unrelated medical marijuana measures that made it onto the ballot. The constitutional amendment will allow patients with cancer, HIV, epilepsy and other conditions access to the drug.
Voters in Utah also were considering whether to legalize medical marijuana. The Mormon church, which carries outsized influence in the conservative state, had opposed the proposal but recently joined lawmakers and advocates to back a deal that would legalize it in the conservative state. Utah's governor said he would call lawmakers into a special session after the midterm election to pass the deal into law, even if Tuesday's initiative failed.