This dam is located on Old Manchester Road/Titusville Road in the Town of LaGrange, NY, in an area also known as “Manchester”.  Maps from the 1800s show a mill located on a pond in this location.  According to historic aerial photos, the pond was drained to be back to just a creek in the 1980s.

More information:  Historic aerial photos

Location: Google Maps (41.683184, -73.866793)