The Minnesota State Fair opens for its 157th year this week. When it closes on Labor Day, about 1.8 million people will have visited. The average daily attendance of 150,000 is tops in the nation — and is close to what some fairs attract over their entire run.

There are other state fairs. In fact, 49 others, although the term is generous.

The Eastern States Exposition in Massachusetts, which includes Connecticut, Maine, New Hampshire, Rhode Island and Vermont, is known as “New England’s Great State Fair” — which, come on, doesn’t even make sense.

Nevada and Michigan went fair-less for several years when their events went bankrupt. Michigan’s returned in 2012 and Nevada’s re-emerged in June. For four days. Baby steps.

Texas claims the biggest fair, with close to 3 million visitors. But it goes on for 24 days, which is kind of like stepping on the scale while weighing giant pumpkins.

So what makes our State Fair such a great state fair? Depends on whom you ask.

Iowa native Jim Kopel has been to all 50 state fairs and rates Minnesota in his top five.

“The education exhibits are just outstanding,” he said.

Education? Not the giant slide? The seed art? The Hamline Dining Hall’s ham loaf?

“No, your educational exhibits are just great,” said Kopel, a retiree from Moline, Ill. “You can tell the kids are having a fantastic time.”

That makes the fair sound more like school than the gut-bombing, nose-assaulting, feet-numbing experience we relish, but Jerry Hammer couldn’t be more pleased.

“What is special about the fair is the way it’s presented,” said Hammer, the fair’s general manager. “You’ll learn things here without even trying.”

Then he got deep: “We need special places to socialize, to learn things, to congregate. You go back in ancient history and we have always had these places. We have one here, and it happens to be in the medium of a state fair. But there’s something deeper than that.”

Fairs with staying power balance traditional hallmarks and modern expectations, Hammer said.

Consider this year’s new all-day Great Yoga Get-Together on Sept. 4, or the designated Selfie Stations. Then there’s the Malt-O-Meal exhibit, where you can sample 15 varieties of the hot cereal invented in Owatonna, Minn., and long manufactured in Northfield.

Marla Calico, president of the International Association of Fairs & Expositions in Springfield, Mo., said that the most successful fairs still champion rural roots, however urban the main audience might be.

She was bowled over by an exhibit of sweet potatoes at the North Carolina State Fair “that was hundreds of times larger than anything I’d ever seen at any other fair.” Soybeans star in the Indiana State Fair’s multimillion-dollar Glass Barn, where fair visitors can talk with soybean farmers in the field via satellite uplink.

As for Minnesota, Calico said, “the DNR Building and related activities present one of the finest examples of showcasing a state’s important natural resources I’ve ever seen.”

Still, nothing may be quite as cutting-edge as the Oregon State Fair’s new exhibit: a display of prize-winning marijuana plants, the pride of the Oregon Cannabis Business Council. (Visitors should expect to hear info about climate, soil conditions and pest control.)

Fairs pre-dated statehood

There was a fair before there was a Minnesota.

The first territorial fair in 1854 sought to encourage settlers and allay concerns that winters were too cold for farming and summers too hot to be healthy.

There was some livestock, corn and pumpkins. There was no Woman’s Building because there were only about 50 women in the area, according to “Blue Ribbon,” Karal Ann Marling’s fascinating history of the fair.

The next territorial fair was bigger, as was the next, and with statehood in 1858, the Minnesota State Fair was born.

By the 1920s, Machinery Hill was considered the world’s largest display of farm equipment. By the 1950s, Princess Kays were the fresh-scrubbed faces of the dairy industry. Today, with an annual budget of $42 million, the fair is a self-supporting entity.

Hammer said that independent status (technically, the fair is a quasi-state agency) is a big reason for its success. Some fairs struggle “if they’re tied closely to state or county government,” as when Michigan’s economy faltered.

The last time the Minnesota State Fair got any government funding was in 1947, and Hammer has a bone to pick with even that laudable record. Here’s the deal:

During World War II, the federal government seized the Hippodrome for an airplane propeller factory. “But to get it in proper shape for manufacturing, they tore the hell out of it,” Hammer said. Because the building was both unusual and essential, the feds reimbursed the fair for the cost of building a new one — hardly a government handout, right? (Now the Warner Coliseum, it hosts the horse shows.)

Fairs aren’t created equal

Minnesota and Iowa may have the most similar fairs — a dozen days of carved butter, beef and hogs, Tilt-A-Whirl and deep-fried foods. Minnesota’s has more visitors, but Kopel favors Iowa’s, where he used to exhibit his own Chester White hogs.

Kopel and his wife visited Midwestern fairs for fun. When she died of cancer, he decided to aim for all 50 in her honor. He rates them on 116 criteria ranging from the frequency of fireworks to the adjacency of manure.

The ratings give Kopel’s visits some structure, but mostly he visits to learn each state’s personality. Under that definition, most fairs excel.

“Oh, you definitely get a sense of a state,” he said. In Alaska, there were no more than 10 animals, “but there were vendors selling these terrific fresh fish sandwiches.”

Kopel’s fair-going ambitions have faded, although he still makes a pilgrimage to the Iowa State Fair. A successful fair, he said, still comes down to families, and agriculture.

“You’ve got the farm families who come and he wants to watch the livestock show and she wants to see the pies being judged, and the kids want to ride the rides,” he said.

“Then you’ve got the city family and they want to walk through barns and they get really excited about the biggest boar and go to the petting zoos and the birthing barn.

“If you don’t have a state fair that has all these things going, it’s going to disappear.”