The extraction of salt from seawater is one of the most direct ways of exploiting the marine environment. In the historic period, the production of salt formed an important component of the global economy. In temperate locations such as Ireland, archaeological evidence of extracting salt from seawater comprises a range of expressions and locations dictated by the energy resource required. This article presents the results of the first archaeological excavations of a saltworks complex in Ireland, at two sites that produced salt from the seventeenth to the nineteenth centuries. Partial excavation of a seventeenth-century complex at Ballyreagh Lower revealed a crude structure that was not capable of supplying all of the area’s needs. By contrast, the eighteenth- and nineteenth-century pan site at Broughanlea shows a step-change in scale, efficiency, and infrastructure that reflects new economic networks in a country predominantly relying on agricultural produce.