The mighty Columbia River flows through all of the following Pacific northwest states except: A. Idaho B. Oregon C. Washington D. British Columbia

The correct answer is - A. Idaho.

The Columbia River is a big river and it flows through the western part of the North American continent. Its path leads it to cross through four federal states, tow of which are Canadian, and two are in the United States. The river starts its flow in Canada, in Alberta, moving in a northwestern direction. After that, it makes a sharp turn and moves in south direction while passing through British Columbia. It crosses the border between Canada and the United States, entering Washington, and after that Oregon, making multiple turns in different direction, and it ends up into the Pacific Ocean.