The Madaket Ditch, formerly spelled as Maddequet Ditch, is a canal connecting Long Pond to Madaket Harbor on the western edge of Nantucket, Massachusetts.
The ditch was first dug circa 1665 by English settlers and Native Americans as the first public works project on Nantucket.
Fish runs have historically included perch, herring, smelt, and eels.
Today the ditch still exists at Second Bridge, with depths between two and four feet.
As it is tidal, there is little variation in water level at the pond's end.