Q. 49th Parallel is the boundary line between which two countries?
Answer: USA and Canada
Notes: The 49th parallel is used as an informal name for the Canadian border with the USA, which is marked out by the parallel line of latitude at 49°N.It forms a border between the Canadian provinces of British Columbia, Alberta, Saskat-chewan, and Manitoba (to the north), and the US states of Washington, Idaho, Montana, North Dakota, and Minnesota (to the south).