In the 1760s Boyne Navigation opened between Slane and Oldbridge, approximately down river. This is a series of canals which made the River Boyne navigable to small boats from Slane to the port in Drogheda. A canal which is part of the navigation runs parallel to the river on the south bank near Slane. David Jebb was the engineer in charge of the construction. Once the navigation was opened as far as Slane Jebb himself built a flour mill at Slane. Slane Mill stands on the north bank of the River Boyne beside the N2 bridge. The mill is a five-storey cut stone building. When the mill was completed in 1766 it was the largest flour mill in Ireland.