Restrictions in Effect Off Grouse Mountain Road 402

 Effective immediately, off-road travel is prohibited off the Grouse Mountain Road, Forest System Road (FSR) 402 on the Powder River Ranger District. This includes no parking of motor vehicles and wheeled equipment for the purposes of dispersed camping within 300 feet of FSR 402. 

The purpose of the restriction is to limit the spread of Ventenata (Ventenata dubia), a non-native, highly aggressive, invasive grass species known to be adjacent to FSR 402. 

Ventenata, an invasive grass new to the Great Plains region, requires treatment to either slow its spread or eradicate.  The area known as Grouse Mountain along FSR 402 from its intersection with Highway 16 leading southeast contains the only known location of Ventenata on the Bighorn National Forest.

“Increased vehicle use within the grassland surrounding FSR 402 has been alarming,” said Acting Powder River District Ranger, Silas Davidson. “Forest managers recognize that these vehicles and people could be collecting seed inadvertently in their tires, undercarriage of vehicles, their shoes and clothing, and in pet’s hair.  These seeds could be transported to other locations where this invasive species does not exist.”

Bighorn National Forest personnel are concerned about the spread of Ventenata in the forest and throughout the region. The Bighorn National Forest is a well-traveled corridor between Yellowstone National Park and forests and parks in the Black Hills area, providing potential opportunity for Ventenata to spread to these well-known ecologically important regions.

For information please call Powder River Ranger District 307-684-7806, check our website,, follow us on Twitter (@BighornNF), or like us on Facebook (US Forest Service – Bighorn National Forest).

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