There's been a breach of state borders in Chicago recently. Montana has invaded.

"I've seen them on the train, and then on the bus, and there's a big billboard, it's somewhere over by Lou Malanati's over there off Lincoln," said Lincoln Park resident Jordhan Briggs. "They're everywhere."

Chances are plenty of Chicagoans have noticed them too--the large billboards featuring a photo of a bear in a creek, or one of Glacier National Park's scenic mountain views. That's by design, explained Katy Peterson, consumer marketing manager for Montana's Office of Tourism.

A Montana tourism campaign started three years ago with about a $300,000 budget in Chicago, Peterson said. The next year, that spending  jumped to $800,000. The total for the most recent year is around $1 million.

"We were in Chicago in a really kind of small way in 2009, but really kind of blew [advertisements] up in spring of 2010," Peterson said. "A lot of advertising is on the sides of buses, and the double-decker tour buses, and buses and train routes, and at the stations, and on bulletin boards."

Chicago is one of four cities--along with Minneapolis, Salt Lake City and Seattle --Montana's Office of Tourism has decided to hone in on, with Chicago's portion eating up about 40 percent of of the total spending in those markets.

Illinois as a whole tied for eighth place in out-of-state visitors in 2010, with about three percent of the more than 10 million of Montana's tourists hailing from Illinois. California leads the pack at nine percent, with Washington one point behind.

But what really sticks out, Peterson explained, is the first-time visitors.

In the summer of 2010, 13 percent of first-time vacationers to Montana came form Illinois--good for the highest percentage.

"What our research shows is, once someone comes to Montana the very first time, 86 percent of them are likely to return in the next two years," she said. "It's a really good strategy for us to focus our dollars into getting someone here for the first time, because data shows they are likely to repeat."

Chicago is also littered with the group's target audience, dubbed the geo-traveler by Peterson.

"Demographically and psycho-graphically, the geo-traveler is highly educated, travels at least three times a year out of state, has a real interest in authentic places," Peterson said. "People who are really looking for--and place a premium on--nature, getting off the beaten path and seeing what a destination really has to offer, instead of picking a box off a list. People who really want to immerse themselves in the travel experience. Montana can really provide that."

To attract a geo-traveler's attention, the ads go all-natural: Real photos (not photo-shopped, Peterson noted) of wildlife and the unique natural landscapes offered in both Yellowstone and Glacier National Park, destinations Peterson described as the state's  "Ace cards."

Played against the  glass, brick and metal of Chicago's paved streets, they certainly stand out.

"I never really thought about Montana as a vacation destination," Briggs said while waiting for the bus. "So it's interesting. It looks pretty."

19-year-old Samantha Rydin sees Glacier National Park every day, out her window, on the billboards across the street.

"I'd go to Montana after seeing those," she said. "It looks relaxing, and pretty. Different than here. So it'd be nice to get away."

That's exactly what Peterson and her colleagues are counting on. Their response: It'd be nice to have you.

Shaymus McLaughlin is a RedEye special contributor