The river is known for its trout fishing, and its estuary on the Irish sea provides a haven for wintering birds.

From there it flows east, breaking into two streams between Gaffney and Beaumont, where it unites again, running adjacent briefly to the R150, and then flows east, crossing under the M1, traveling through Dardistown Cross, past Rockbellew, and runs parallel to the Duleek Road near Julianstown.

[6] From Julianstown, the side of the Nanny is marked by gray, thick-bedded crystalline limestone, freely exposed, and dipping northwards at 15 degrees.

During the Williamite Wars, after the Battle of the Boyne, the Jacobite army retreated from the field and headed for the bridge at Duleek, to cross the Nanny.

[8] According to legend, Saint Patrick had cursed several of the rivers in Meath, including the Nanny, for their deficit of fish.

The shore line, approximately 500 metres (1,640 ft) at low tide mark, includes beach and intertidal habitats.