One of the smaller still active canals in the Eastern portion of upstate New York is called the Champlain Canal.  It is about 60 or so miles and starts at the Hudson River in the south and ends at Lake Champlain in the north.  In the background (to the west) are the Adirondack Mountains.

Here is an informative site.

http://www.champlaincanal.org/

Also, check this site out as well.  Lakes to Locks covers the Champlain Canal as well as Lake George and Lake Champlain.  It runs north/south in between Montreal and New York City.

http://www.lakestolocks.org/content_detail.php?uid=ltl58D33A7C3C89E69A9