Head up the road 60 miles northeast of Denver and you come to a place of cattle ranches and oil fields. In many ways, it's like stepping into the Old West. And just like in the Old West, neighbors here don't always see eye to eye.
In the conservative farm town of Greeley, Colo. residents are leery of Amendment 64, the historic measure that legalized the retail sale of marijuana to adults over age 21.
"We're legalizing marijuana today, OK? What's the next drug we're going to legalize?" asks Greeley Police Chief Jerry Garner.
Greeley is one of roughly a third of Colorado municipalities that have prohibited commercial marijuana growing and dispensaries.
Garner thinks there are still too many unknowns about marijuana.
"There's so much we don't know about the stronger pot available out there today," he said. "We don't know what effect it's going to have on youngsters that get a hold of it."
It's a position that's in keeping with Greeley's roots, which go back to its founding in 1870 as a temperance colony. The town didn't legalize the sale of liquor until 1969, more than three decades after Prohibition ended.
But while Greeley has a history of shunning sin, its neighbor Garden City is known for celebrating it.
"Garden City was always that place where you could let your hair down and do things a little bit differently," says Brian Seifried, Garden City's mayor.
"There have always been some rumors of a bit of a seedy background when there was some gambling and houses of ill repute, and even rumors of some tunnels to Greeley so people could enjoy Garden City's benefits without being seen."
Garden City was founded by a bootlegger named A.F. Ray. When Prohibition ended, and Greeley remained dry, Ray decided to incorporate his own town.
And now history is repeating itself.
In January, Garden City saw its first legal retail sale of recreational pot in northern Colorado, at the soon-to-be-named XG Platinum. More than a dozen customers waited outside before doors opened.
XG is one of four marijuana dispensaries in a town less than a mile long. The largest one is Nature's Herbs and Wellness Center, owned by John Rotherham. He says Garden City has stayed true to its roots.
"They embraced medical marijuana when it came along. My wife and I went to 14 different cities, and everyone was placing moratoriums on them. Garden City—they were one of the very first ones to embrace it and license it," Rotherham said.
With 45 workers, he is the largest employer in town. It's a bustling family business, where his mother, father, aunt and uncle gather to trim bud.
Rotherham, a small businessman who once ran grocery stores and restored automobiles, says he never expected to become a marijuana mogul.
"It's really surprising to hear your mother say, "Boy, we have really nice buds today," he said.
He has had to build a new greenhouse just to keep up with the demand he's expecting from recreational marijuana. Over the coming year, he plans to triple or quadruple in size.
"I never planned on being this big. But you just have to grow with the demand."
Each joint and edible sold means tax money for the state and towns like Garden City, where taxes levied on medical marijuana already fund a third of the budget. With new retail sales, the mayor expects that number to rise.
The blue collar town is putting that money toward revitalization. Among other initiatives, it's offering matching renovation grants to homeowners and businesses. The mayor points to the new facade at the historic White Horse Bar as one example of a business that has taken advantage of the resources.
A windfall like that would tempt most town leaders, but not in Greeley.
"To have a community based on a tax structure that depends on the sale of marijuana, I think, is inappropriate," Greeley Mayor Tom Norton said.
While Garden City cashes in, Greeley has decided the wages of sin aren't worth the trouble.
Garner says he understands the arguments that marijuana is safer than alcohol, but he still has serious concerns about legalization.
"I've already got one legal intoxicant out here that's causing all kinds of problems in society," the police chief said. "Now I'm going to have another one out there. So what kind of mayhem is that going to cause?"
And for those who might view him as old-fashioned and out of touch with the new reality, Garner insists this isn't a question about personal morality—it's about public safety.
"I have no religious compunctions that marijuana is the devil's weed, it's evil and all that. My job is to keep people safe," he said. "And I worry that people are going to be less safe in my city, the city I'm responsible for because it's easier to get access to marijuana."
—By Na Eng, special to CNBC.com
CNBC and correspondent Harry Smith tell the story behind this controversial and stunning development and report on the exploding legal pot market. Watch "Marijuana in America: Colorado Pot Rush" on Feb. 26 at 10 p.m. ET