The Congested Districts Board was set up in 1891 to develop economic activity in the poorest areas of Ireland and those most badly affected by the great famine of the 1850s. They established the herring and mackerel curing station on Glassillan in 1897. They also built another curing station at the Old Pier at the east end of Bofin Harbour. I'm haven't been able to find out when they stopped being used. The curing station and causeway at Glassillan were badly damaged in the storms of 2014.
Looking south down the broken causeway
Ruins of the Curing Station on Glassillan
Glassillan from East End Bay Beach
Ruined Curing Station