South Dakota is the only state President Obama hasn’t visited since taking office.

As far as South Dakota is concerned, that just means the president was saving the best for last.

“If he wants to come for a day, that’s fine, but to really do South Dakota right, he’s going to need at least a week,” said South Dakota Tourism Secretary Jim Hagen, who extended an invitation to the White House earlier this year, after the president made a swing through Utah — the 49th state on his to-visit list.

The invitation was accepted. On May 8, the president will be the commencement speaker at Lake Area Technical Institute in Watertown, a small two-year school with a graduation rate almost double the national average.

There are places the president visited earlier, and places he’s visited more often — he’s made eight trips to Minnesota since taking office, for those keeping track — but you’d be hard-pressed to find any town, anywhere, more excited about a presidential visit than Watertown, S.D.

Volunteers are out in force, picking up trash and sprucing up this city of 21,000 ahead of the president’s arrival. Streets crews have been working double shifts for weeks, sweeping and repainting every route the presidential motorcade might possibly travel.

“This is a big deal for us,” said Watertown Mayor Steve Thorson, who has a long list of places he’d love to show the president while he’s in town: the Bramble Park Zoo, the art museum, the business park near the airport, the new National Guard armory. Then maybe a microbrew at Dempsey’s and a burger at the Wheel Inn? But given the president’s tight timetable, the college campus might be the only sight he really gets to see in town.

Which is fine, Watertown officials say. This might be a big day for the town, but it’s a bigger day for the graduates. Meanwhile, the president who got 40 percent of the vote in this county is going to get 100 percent of the Welcome Wagon, as local residents break out the bunting and welcome signs and watch with interest as Secret Service agents scout out their town.

“We wish he could stay longer,” said Karen Witt, executive director of the Watertown Convention and Visitor’s Bureau. “We’re a nice, friendly, safe community.”

For South Dakota, getting visitors into the state has always been the real challenge. Once they’re in, locals can hook them with the arid beauty of the Badlands or reel them across the state as they follow the signs for Wall Drug and its promise of free water and 5-cent coffee.

“One thing we have learned is that if we can get them to the state, we’ve got a very high probability of keeping them,” said Pat Costello, commissioner of the Governor’s Office of Economic Development, whose team just came up with an eye-catching ad campaign to recruit new residents to the state by touting all the ways life in South Dakota beats a one-way trip to lifeless, airless Mars.

“South Dakota: Progressive, productive and abundant in oxygen,” boasts the ad campaign, which officially launched Friday. “Why die on Mars when you could live in South Dakota?”

Maybe next year, President Obama will be back for the 75th anniversary of Mount Rushmore. Maybe he’ll swing back through Watertown and take a boat out on Pelican Lake.

But for now, South Dakotans are just happy they made the list.

“It’s a thrill to have any sitting president visit your state,” Hagen said. “They said he’d come and they kept their promise.”