Big Sky, Big Growth: How Montana’s Newcomers Are Shaping Its Senate Duel

Growing up in Bozeman, Mont., Dylan Heintz loved the picturesque views of the snow-capped mountains and the small-town charm. Things were cheap: His dad bought the family home for about $80,000.

These days, Bozeman feels less quaint. A steady stream of out-of-state transplants to Big Sky Country became a deluge during the pandemic, leading to soaring prices, a boom in luxury apartments that blot out the rustic scenery and a rash of higher-end businesses like Whole Foods. Drawn by Montana’s natural beauty and easy access to outdoor activities, the newcomers have created an affordability crisis and a local backlash that are transforming the state’s economy and politics.

“I love this place, but it’s just a tough place to live in,” said Mr. Heintz, 28, an auto body repairman. Rent has doubled in his trailer court, and he and his wife cannot afford to buy a home in town, leaving them considering a move to Florida. “There are a lot of out-of-staters that have some money, and they’re willing to pay above asking price. That definitely hurts people.”

The fresh population of wealthier residents — often retirees, technology workers able to do their jobs remotely and other big-city transplants — is one of the largest question marks hanging over Montana’s crucial race for Senate. As Jon Tester, the Democratic incumbent, looks to fend off Tim Sheehy, a businessman and retired Navy SEAL who is expected to capture the Republican nomination, tensions over the exploding growth will be a top issue in November.

And how the new Montanans vote could prove decisive.

On the surface, their presence might seem to benefit the embattled Mr. Tester, because a sizable chunk of them — 35 percent of arrivals in 2022 — hail from left-leaning states like