As long ago as the 18th. century the twin branches of herring fishing and herring curing was carried out on Lough Swilly. The lough would be crowded with sailing smacks from Great Britain, the Isle of Mann and even from Norway

In 1902 Scottish smacks operating from the lough located huge herring shoals of good quality and the industry developed, rapidly, with steam drifters replacing the sailing craft. Between 1908 and 1914 there were over 200 vessels working out of the lough. The First World War interrupted fishing but 1920 saw the resumption of operations with 1927 being the boom year for the industry.

Each drifter carried a nine man crew with the engineer, cook and fireman drawing wages and the other hands being paid shares. The drifters laid nets up to a mile in length which were allowed to drift with the tide.

The herring trade provided a considerable boost to the local economy as each vessel had to be coaled and stored locally. Local tradesmen also provided the infrastructure for maintenance and repair. The fish themselves were auctioned in crans which were equal to four baskets. The Donegal herrings were so large that only 750 were needed to fill a cran as opposed to around 1000 of the fish caught around Britain.. This was attributed to the considerable influence of the Gulf Stream providing the herring with an abundance of food.