I don't think of us having any mountains nearby. Prince Edward County is on the other side of the Lake and on the Bay of Quinte, close to Belleville is a lake that is 200 feet (60 metres) above the water of the Bay of Quinte. That's high enough for me to justify the name Lake on the Mountain. Think of Niagara Falls - it is 167 feet tall. Of course, it isn't the height of Niagara, but the expanse of it and the speed of the water as it hurls along at whiplash speed. That's what makes it so spectacular an experience.
Lake on the Mountain, being on the other side of Lake Ontario at Glenora, has Northern Ontario terrain and northern forests. The lake is deep - it is 37 metres deep and just over one square kilometre in size. Stories of how the lake was created include volcanoes, meteorites, and glacial whirlpools. The most accepted theory is a collapsed doline - a limestone rock feature in areas with limestone foundations. Another way of thinking of it is that it is a type of sinkhole.
So we have our own mysterious lake on a mountain very close by. Here's a youtube video showing where it is located HERE. The ground view youtube video is HERE. It is most amusing as the comments from Tavel Canada indicate a boring drive along the 401 to get to the destination. That does describe the 401 east of Toronto for me.
This is a Niagara lakeside picture the southern side of Lake Ontario and below it, near Kingston on the north side.