Why isnt Plattsburgh NY part of the Adirondack Mountains? -

I used to think when I was younger the Adirondack Mountains extended all the way to the Canada border.But I have discovered the Adirondack Mts. end before Plattsburgh and do not extend to the border.Does anyone know why the Adirondack Mts. don t go all the way to the Canada border? (in NY)

The Adirondack Mountains do extend all the way up to the border. On the Canadian side of the border is the Laurentian Mountains.However Adirondack Park does not extend all the way to the border. And that s probably where your confusion lies.