Although some non-definitive sources such as Google Maps show the river originating directly at Henderson Lake, per the U.S. Geological Survey (USGS), the river cartographically begins at the confluence of Indian Pass Brook and Calamity Brook near the outlet of Henderson Lake in Newcomb, Essex County, New York, in the Adirondack Park.
The longest source of the Hudson River as shown on the most detailed USGS maps is the “Opalescent River” on the west slopes of Little Marcy Mountain, originating two miles north of Lake Tear of the Clouds, and a mile longer than “Feldspar Brook”, which flows out of that lake in the Adirondack Mountains.
Popular culture and convention, however, more often cite the photogenic Lake Tear of the Clouds as the source.
Sailing With Devious, 2014 