title: Mattock River
text: # Mattock River
  
  The Mattock River is a river in Ireland. It is a tributary of the River Boyne.
  
  Its source is near Collon (53°46′30″N 6°29′42″W﻿ / ﻿53.775°N 6.495°W﻿ / 53.775; -6.495), 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 and Louth. Here it turns towards the southwest until Monknewtown where it takes a southeastern direction again before turning roughly east at Dowth. It joins the River Boyne at Oldbridge in the parish of Drogheda (53°43′15″N 6°25′39″W﻿ / ﻿53.7207°N 6.4276°W﻿ / 53.7207; -6.4276). The estimated terrain elevation above sea level is 10 metres.
  
  