By the early 1990s, a growing concern and recognition among land managers and county governments arose with regard to noxious weeds degrading our cherished natural resources and negatively impacting our economic base. To manage the weed problem would require effectively dealing with large areas of land, multi-jurisdictional boundaries, rapid weed spread, and limited budgets. Most of all it would require something that had been lacking, cooperation among all land managers and landowners. Due to these concerns, the local governments of Baker, Union, and Wallowa Counties, along with the Bureau of Land Management, Oregon Department of Fish & Wildlife, Boise Cascade, and the US Forest Service, agreed to form a cooperative weed management area.
The Tri-County CWMA was formed by Intergovernmental Agreement under the legal authority of ORS 190.010, in December of 1994. Memorandums of Understanding between the Tri-County CWMA and many agencies and cooperators are also in place.