The Mattock River is a river in

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

. It is a tributary of the

River Boyne The River Boyne ( or ''Abhainn na Bóinne'') is a river in Leinster, Ireland, the course of which is about long. It rises at Trinity Well, Newberry Hall, near Carbury, County Kildare, and flows north-east through County Meath to reach the ...

. Its source is near

Collon Collon () is a village and townland in the south west corner of County Louth, Ireland, on the N2 national primary road. The village is home to the Cistercian Abbey of New Mellifont, and to Collon House, the ancestral home of the Foster family. ...

(), from where it flows through County Louth towards the southeast until a place west of Drummond Tower in Coolfore where it begins to form the boundary between Counties

Meath County Meath ( ; or simply , ) is a Counties of Ireland, county in the Eastern and Midland Region of Republic of Ireland, Ireland, within the Provinces of Ireland, province of Leinster. It is bordered by County Dublin to the southeast, County ...

and

Louth Louth may refer to: Australia *Hundred of Louth, a cadastral unit in South Australia * Louth, New South Wales, a town * Louth Bay, a bay in South Australia ** Louth Bay, South Australia, a town and locality Canada * Louth, Ontario Ireland * Cou ...

. Here it turns towards the southwest until Monknewtown where it takes a southeastern direction again before turning roughly east at

Dowth Dowth () is the site of Neolithic passage tombs near the River Boyne in County Meath, Ireland. It is one of the three main tombs of the ''Brú na Bóinne'' World Heritage Site, along with Newgrange and Knowth. Its features align it with the ot ...

. It joins the River Boyne at

Oldbridge Oldbridge () is a townland near Drogheda in County Meath, Ireland. The area is home to the Boyne Navigation, the Battle of the Boyne Interpretive Centre and the southern half of the Mary McAleese Boyne Valley Bridge (which carries the M1 motor ...

in the parish of

Drogheda Drogheda ( , ; , meaning "bridge at the ford") is an industrial and port town in County Louth on the east coast of Ireland, north of Dublin. It is located on the Dublin–Belfast corridor on the east coast of Ireland, mostly in County Louth ...

(). The estimated terrain elevation above sea level is 10 metres.

References

{{Reflist Rivers of County Louth Rivers of County Meath