| Ballynahinch Lake | |
| Pushpin Map: | Island of Ireland |
| Pushpin Map Alt: | Ballynahinch Lake location in Ireland |
| Pushpin Label Position: | none |
| Pushpin Map Caption: | Location in Ireland |
| Location: | County Galway |
| Inflow: | Derryclare Lough |
| Outflow: | Owenmore River |
| Catchment: | 155.23km2 |
| Basin Countries: | Ireland |
| Length: | 3.9km (02.4miles) |
| Width: | 0.9km (00.6miles) |
| Area: | 1.7km2 |
| Elevation: | 7m (23feet) |
Ballynahinch Lake is a freshwater lake in the west of Ireland. It is located in the Connemara area of County Galway.
Ballynahinch Lake measures about 4km (02miles) long and 1km (01miles) wide. It is located about 10km (10miles) east of Clifden and about 60km (40miles) northwest of Galway city. The Twelve Bens mountain range lies to the north of the lake, with Benlettery directly overlooking. Ballynahinch Castle lies on the west shores.
Ballynahinch Lake is fed by Derryclare Lough at its eastern end (which is in turn fed by the neighboring Lough Inagh), and it drains to the south via the small Owenmore River – also called the Ballynahinch River, and not to be confused with the Owenmore River (County Mayo) – which in turn enters Bertraghboy Bay.
Fish species in Ballynahinch Lake include salmon and brown trout. Ballynahinch Lake is part of The Twelve Bens/Garraun Complex Special Area of Conservation.