The new expanded geographic range for the Yellowstone National Park bison adds almost an additional 400 square miles for the bison to roam year round in Montana. According to the Decision Notice for the Year Round Habitat for Yellowstone Bison Environmental Assessment, here is what the official boundaries will be:
- Year-round access to Horse Butte, and north along U.S. Highway 191 up to and including the Taylor Fork Drainage, as well as the Cabin Creek Wildlife Management Area and the Monument Mountain Unit of the Lee Metcalf Wilderness
- Bull Bison will have year-round access within the Gardiner Basin from the northern boundary of YNP to the southern entrance of Yankee Jim Canyon. All bison will be managed to prohibit travel north of the hydrologic divide (i.e. mountain ridge-tops) toward Dome Mountain/Paradise Valley and Tom Miner Basin.
- However YNP bison will not be permitted south of the south fork of the Madison River outside of YNP, and in that area will continue to be managed under the 2000 IBMP Record of Decision.