Inner Dundalk Bay is a significant estuarine and coastal water body in County Louth, Ireland, covering an area of approximately 33.35 square kilometers. It is a designated Natura 2000 site and forms a critical part of the Castletown River estuary system. The bay's substrate is characterized by marine sands and gravels, with extensive deposits of marine and estuarine silts and clays, creating a diverse habitat of mudflats, channels, and intertidal zones. As a nutrient-sensitive area, its water quality is under ongoing review, with the inner bay currently classified as "At Risk" under the Water Framework Directive. This estuarine environment supports a mix of marine and migratory fish species, making it a notable destination for inshore angling.