St Johnston, officially Saint Johnstown, is a village, townland, and an electoral division in County Donegal, Ireland. It is in the Laggan district of East Donegal on the left bank of the River Foyle. It is in the civil parish of Taughboyne and barony of Raphoe North, on the R236 road where it overlaps the R265 road. The village is about 12 kilometres south of D…St Johnston, officially Saint Johnstown, is a village, townland, and an electoral division in County Donegal, Ireland. It is in the Laggan district of East Donegal on the left bank of the River Foyle. It is in the civil parish of Taughboyne and barony of Raphoe North, on the R236 road where it overlaps the R265 road. The village is about 12 kilometres south of Derry.