Lough Fern is a shallow lake – two metres deep on average, three at the most – threaded onto the River Leannan about 2km south of Milford and 10km north of Letterkenny. It runs 2.3km long and 0.8km wide, sits at just under 19m above sea level, and drains back down the Leannan to Lough Swilly at Rathmelton. Be clear about what it is before you go: this is a wildfowl refuge and a fishery, not a scenic honeypot, with the water and the birds and not a great deal else.
The islands
There are two small islands at the northern end of the lake. They are part of the protected wetland, so keep off them and view from a place where you have permission to be.
Birds and conservation
Lough Fern is a Special Protection Area. The National Parks and Wildlife Service lists pochard (Aythya ferina) and other wetland birds among the reasons for the designation, and the lake sits within the wider Leannan River Special Area of Conservation. The marshes and reedbeds at both ends feed and roost wetland birds through the colder months. Give roosting birds plenty of space, keep noise down in winter, and bring binoculars if it’s the birds you’re after.
Fishing
Check Inland Fisheries Ireland for current Leannan rules before making plans. The river system had restricted salmon and sea trout fishing in 2026. Confirm local access and permissions before fishing, and use land or launch points only where you have permission. Below the surface the lake is known to hold brown trout, salmon, perch, three-spined stickleback and the critically endangered European eel.
Walking
There is no made path around the lake, and no walking route is promoted here. For a marked walk in this part of Donegal, see Glenveagh National Park.
Practical information
- Access: check local access and permissions before you go, and do not stop on the road in a way that blocks traffic or gateways.
- Facilities: none known at the lake, so bring whatever you need with you.
- Wildlife etiquette: as a protected SPA and SAC, keep it quiet in winter when the birds are roosting, stay off the islands, and keep dogs under control.
- Safety: the water stays cold year-round and deepens towards the middle; it’s not a swimming lake.
Winter, when the pochard are on the lake, is the season for the birds, but only watch from where you have permission to be.