The streams that cross lands at Kilcoole, optimistically referred to as rivers, would have had an important part to play in determining the location of settlements. In early times they were important for watering livestock, powering mills, and for the daily tasks of washing, bathing, and drawing water for drinking. Eels and salmon used to frequent these streams and fishing would have been an important source of food and pleasure. The area is blessed (or perhaps cursed) with an abundance of fresh water, including the many wells or springs which were used for drinking water up to the last century.

Two local streams have historical significance in the Kilcoole area. From north to south these are (click here for map):

Cannistown River (Kilcoole Stream, St Patrick’s River, Knickitty River). This stream has played an important part in the development of certain landmarks in Kilcoole. The origins of the name Cannistown have not been uncovered, but it may be another spelling of Kennystown after a family named Kenny, Kenna or Keane. The water develops at the bottom of Downs Hill, flows east to the north of Kilpedder, runs between the townlands of Priestnewtown and Kilquade, then turns south toward Kilcoole. A short tributary joins it from the north near the walled garden on the Mass Path. Some of the water is here diverted into the walled garden and out again.

Due west from the bottom of what is called New Road, the Cannistown originally split in two. The northern branch flowed under Main Street just to the north of Doyle’s public house, near the intersection with Sea Road. The road bridge crossed the stream and part of this stone wall can still be seen along Main Street. From here, the north branch flowed to a corn mill located just to the east along Sea Road. This mill existed before 1798 and closed in 1908. One of the round mill stones can still be seen under the sign for Beachdale and Meadowbrook estates. From the mill the water ran southeast. The old river branch exists today as a small stream coming from Wellfield across Sea Road and into a back garden, then along the northern boundary of Meadowbrook estate. This stream runs between Meadowbrook and Holywell, rejoining the other branch of the Cannistown just east of the Holywell roundabout. This northern branch was diverted in the late 1900s and little sign remains of it today.

The southern (now main) branch of the Cannistown flows around Kilcoole proper to the south, before turning to cross under both the Newtown and Newcastle roads. The river is still clearly visible today though nearly impossible to access from the road. From the Newcastle road the stream flows through Beachdale and Meadowbrook, rejoining its northern branch just east of Holywell estate. The reunited river then flows past a water treatment plant and on into the north side of the brackish marsh, connected to the sea at the Breaches. This lower stretch is often referred to as the Knickitty.

Newtownmountkennedy / Woodstock river. Visitors to Woodstock Estate (Druids Glen golf club) will be familiar with the many water features there, a result of this river as it flows from Downs Hill to the Breaches. This same stream is a prominent river in Newtown Mount Kennedy, forming a magnificent glen at Altidore Estate before winding down past a popular walking trail in the woodlands at Mount Kennedy demesne. Later the river arcs below the village and on past the ruins of a mill in the valley at Newtown. From that village the river runs in the valley south of the Kilcoole road, then strikes due east through Woodstock Estate and on to the Breaches.

Both the Cannistown and Newtown streams appear on the Downs Survey map of 1660. In addition to the protection afforded by the Rock of Kilcoole, the presence of a stream flowing nearby must have been an important factor in the original settlement of Kilcoole village.