Gianforte, Montana sue Yellowstone National Park over its bison management plan

A long-simmering battle between Yellowstone National Park officials and the Gianforte administration in Montana came to a head on Tuesday with state officials suing the park in federal court for its bison management plan.

The new case, filed in federal court in Billings, argues that park officials have intentionally cut Montana out of management plans or ignored the park’s own science in an effort to boost Yellowstone National Park bison numbers and skirt vaccinating them against brucellosis, a disease of concern to the state’s cattle-ranching industry.

The court action follows public disputes and disagreements between the Gianforte administration and federal officials, including other members of the Interagency Bison Management Plan.

While park officials manage the herds in Yellowstone National Park, at issue is what happens when the bison inevitably roam across the border of the park, often into Montana. Yearly bison hunting has also generated a fair amount of outrage as advocates for the nation’s official land mammal, the bison, decried what they said was a slaughtering line of hunters lined up on the Montana side of the park’s border to hunt them as they crossed the boundaries.

The heart of the lawsuit, filed by Gianforte’s attorneys as well as attorneys for the Montana Department of Livestock and the Montana Department of Fish, Wildlife and Parks, contends that Yellowstone officials have unlawfully disregarded a 2000 agreement to keep the Yellowstone National Park bison herds at less than 3,000 animals, as well as a commitment by park officials to vaccinate bison against brucellosis. Instead, the lawsuit argues that a new environmental impact statement adopted by the National Park Service in 2024 arbitrarily changed those rules to allow an increase in bison numbers and no requirement for vaccination. State officials allege that Yellowstone National Park also adopted these new rules, saying that they were not materially different than current park practices, which the state of Montana disputes.

“Over the last 20 years, Yellowstone National Park has utterly failed to manage to the specified target population or implement critical elements of its plan,” the lawsuit said.

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