Donaghadee was the original site for regular ferry crossings to Scotland, which started from here, over to Portpatrick, in 1662. It had issues though, with wind direction & accessibility, particularly for larger vessels.

It would be the Post Office who eventually stepped in and improved the harbour at Donaghadee,in 1825. The lighthouse was added in 1836 and is…

…built of cut limestone, fluted, and in its early days was unpainted in natural grey colour. Today the tower, including the lantern and dome, is painted white with a black plinth, a decision which was taken some time between 1869 and 1875.

from the ‘commissioners of irish lights’ website

Nearly 100 years after being built, Donaghadee became the first Irish lighthouse to be electrified, in 1936. This also greatly enhanced the power of the light from “1000 to 20000 candelas.”

Oh, and here’s the view in the other direction: