Cullin lies adjacent to the L22 from Foxford to Pontoon. It is a large, shallow lough of over 2,000 acres and access to it is from the north shore only. There are three access points. The first is at Drummin off the Foxford-Pontoon road. The second is at Pontoon Bridge, and is a footpath only. The third access is off the Pontoon-Castlebar road. There is a new boat mooring and access road beside the old ballroom at pontoon. Cullin holds an excellent stock of brown trout averaging ¾ - 1 lb with some fish to 4 lb. It also gets a run of salmon, both spring and summer fish. In fact, all the fish heading for Lough Conn and its inflowing rivers must pass through Cullinand that can be an awful lot of fish. Many of them rest in Cullin on their way. The best fishing area is from Drummin on the east, northwards by Pontoon to Garrison Island on the western side. The southern half of the lough is not considered to be good fishing. The trout are free-rising and the best season is from April to mid-June. The trout feed well on lake olives in April and the mayfly hatch begins especially early on Cullin – about 15 May. Wet Mayfly patterns can be especially good at this time and it is not unusual for a boat to take maybe a dozen and a half trout in a day’s fishing. A south wind is best, but fishing can be good in any wind.
Salmon are frequently taken on the fly when trout fishing – especially the fresh grilse in June – and a leader of 8 lb BS is recommended. The two hot spots for salmon are at the inflow from Lough Conn at Pontoon Bridge and again at the outflow upstream of the Railway Bridge. Access to the lough at the Railway Bridge is via Corlummin village near Foxford. Salmon are taken at each of these locations from April on fly, spinner, worm and prawn.
The fishing on the lough tapers off about mid-June. The shallows and dangerous rocky areas have all been marked with iron bars to make the lough safe for boat anglers. It is advisable to take special care in high-water conditions, when large unmarked rocks may be lurking jut underneath the surface. Boat and boatmen are available for hire locally at Pontoon Bridge Hotel. Seasons are from 15 February to 10 October for trout and from 1 February to 30 September for salmon. There is a 10 inch size limit for trout.
Excerpts taken from "Trout & Salmon Rivers of Ireland, an angler's guide" by Peter O'Reilly.