The Gustafsen Lake Standoff was a confrontation between the Royal Canadian Mounted Police (RCMP) and the Ts'peten Defenders in the interior of British Columbia, Canada, at Gustafsen Lake. The standoff began on August 18, 1995, and ended on September 17, 1995. The RCMP operation would end up being the most costly of its kind in Canadian history having involved 400 police officers and support from the Canadian Military (under Operation Wallaby).