State
New York Historical Society Facebook
Region
The Hudson River Valley Institute
The Hudson River Valley Institute Facebook
Hudson River Valley Heritage Facebook
Greater Hudson Heritage Network
Dutchess County
Dutchess County Historical Resource Survey of 1986
Dutchess County Aerial Views back to 1936
Dutchess County Ancient Documents Search
Dutchess County Historical Society
Dutchess County Historical Society Facebook
Local Area
Consortium of Rhinebeck History
Red Hook History Facebook Group
Town of Washington Village of Millbrook Historical Society Facebook
Little Nine Partners Historical Society, Pine Plains
Stanford Historical Society Facebook
Columbia County & Surrounding Towns
Columbia County Historical Society
Columbia County Historical Society Facebook
Germantown History Department Facebook
Roeliff Jansen Historical Society, Copake Falls
Roeliff Jansen Historical Society, Copake Falls, Facebook
Milan-Specific
Milan Bicentennial Committee Facebook Page
Milan Bicentennial Committee Facebook Group
1800’s Dutchess County Maps
1829 Burr New York Public Library
1839 Burr New York Public Library
1850 Gillette Library of Congress
1858 Gillette Library of Congress
1867 Beers Rumsey Map Collection
Milan NY History 
Consider adding the Copake History Facebook page to your list. Historian Howard Blue has been publishing it for five years.
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Thank you, this is now added! Great to know thank you! https://www.facebook.com/Copakehistory/
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Thank you,
Howard
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