In the afternoon of 1 September 1978, Phil Gordon and his son Geoffrey were fishing near their camp at Mosquito Lake in the Salmon-Trinity Alps Wilderness Area, Trinity County, California. This area is at an elevation of 6600 feet (2010 m), about 7 miles west of the Scott Mountain summit on county highway 3. The 20-acre lake is in a small glacial cirque basin below a crest that divides Siskiyou and Trinity counties.