(plural uncharted waters)
- An area of sea that has not been surveyed, or those the details of which have not been entered on nautical charts
- (figuratively, by extension) any unknown and potentially dangerous situation.
- 1900 That is the rock that he is in danger of, for he is going recklessly over uncharted waters. - Walter Hines Page, Arthur Wilson Page - The World's Work ...: A History of Our Time