DONAGHADEE, a market town of Co. Down, Ireland, in the north parliamentary division, near the south of Belfast Lough, on the Irish Channel, 25 m. E. by N. of Belfast by a branch of the Belfast and Co. Down railway. Pop. (1901) 2073. It is the nearest port in Ireland to Great Britain, being 21½ m. S.W. of Portpatrick in Wigtownshire. Telegraph and telephone cables join these ports, but a regular passenger route does not exist owing to the unsuitability of Portpatrick. Donaghadee harbour admits vessels up to 200 tons. On the north-east side of the town there is a rath or encampment 70 ft. high, in which a powder magazine is erected. The parish church dates from 1626. There are two holy wells in the town. The town is frequented as a seaside watering-place in the summer months.