Lost Rivers Cooperative Weed Management Area Updated:03/2020

The Lost Rivers Cooperative Weed Management Area covers approximately 2.1 million acres of the Big and Lost River Valleys including all of Butte County and portions of Custer and Lemhi Counties. The purpose of the Lost Rivers CWMA, as per the Strategic Plan, is “To defend the landscape of the Lost River Valleys from invasion by exotic plants and noxious weeds.” To assist in this objective the LRCWMA seeks participation of all who have a vested interest or responsibility in protecting these resources.

A majority of the LRCWMA is federally managed by the Bureau of Land Management, the U.S. Forest Service, the National Park Service and the Department of Energy. Representatives from each of these agencies are actively involved within the LRCWMA and have dedicated programs committed to the management of noxious weeds. Butte, Custer and Lemhi Counties are engaged, through respective weed departments, in supporting the CMWA. Numerous private landowners actively participate in LRCWMA noxious weed control projects by helping to identify and manage noxious weed infestations.

The presence and prevalence of noxious weeds varies throughout the LRCWMA. Prioritization of the use of limited resources for noxious weed control is based upon several factors including the potential for spread, rate of spread, species prevalence in an area and practicality in controlling a species. Management and priority of the various noxious weed species occurring within the LRCWMA varies within species of primary concern are (in order of prevalence):

  1. Canada Thistle
  2. Leafy Spurge
  3. Spotted Knapweed
  4. Whitetop
  5. Russian Knapweed
  6. White Bryony
  7. Black Henbane
  8. Houndstongue
  9. Scotch Thistle
  10. Musk Thistle
  11. Diffuse Knapweed
  12. Rush Skeletonweed
  13. Saltcedar
  14. Yellow Toadflax
  15. Perennial Pepperweed
  16. Dalmatian Toadflax
  17. Dyer’s Woad

Lost Rivers CWMA Board Contact
Brad Gamett
Executive Board Representative
PO Box 832
Arco, ID  83213
Phone: 208-527-8587
Cell Phone: 208-497-8316
Fax: 208-527-3469

Weed Superintendents

Custer County
Casey Kristofferson
P.O. Box 385
Challis, Idaho 83226
Office Phone: 208-879-5229
Fax: 208-879-6413
Cell: 208-833-5229

Lemhi County
Jeremey Varley (Webmaster)
200 Fulton St. Ste 201
Salmon, Idaho 83467
Office Phone:  208-756-2815 ext 282         
Fax: 208-756-6915     
Cell: 208-993-0950

County Extension Contact Information

Butte County Extension Office

Custer County Extension Office

Lemhi County Extension Office

Contact Lost Rivers Cooperative Weed Management Area

REMINDER: This listing is a free service of IdahoLandCAN.
Lost Rivers Cooperative Weed Management Area is not employed by or affiliated with the Idaho Land Conservation Assistance Network, and the Network does not certify or guarantee their services. The reader must perform their own due diligence and use their own judgment in the selection of any professional.


Contact Lost Rivers Cooperative Weed Management Area

Mark Wheeler
Butte County Weed Superintendent
2570 N. Hwy 93
Arco, ID  83213
Phone: 208-527-8595
Cell Phone: (208) 589-0565

Service Area

Services provided in:
  • Butte County, Idaho
  • Custer County, Idaho
  • Lemhi County, Idaho