Lough Conn lies in the shadow of Mount Nephin of the Nephin Beg range and anywhere on the lough the landscape is dominated by its presence. The lough is the smallest of the three great loughs on the western seaboard but still an impressive nine miles long and four miles at its widest point. It has a surface area of fifteen square miles and can be a very daunting place for the newcomer. The main source of the lough is the river Deel which enters the lough in the northeast corner and this is probably the main spawning river for Brown Trout and Salmon on the system. At the southern end of the lough it drains into Lough Cullin at Pontoon and in turn, Lough Cullin, at its Southern end, flows into the River Moy.
Some fifty odd years ago Lough Conn originally flowed into Cullin under a bridge known as Six Arch Bridge but to eliminate winter flooding in the region the Board Of Works blasted a channel through the rock into Lough Cullin to the west of the original bridge and this had the effect of lowering the water level by about six feet.
The recent history of the lough has been rather unstable since the advent of Ireland entering the EU in the early seventies. This caused local farming activities to intensify and by the mid eighties the lough was heavily polluted. Fortunately, Zebra mussels found their way into the water and the condition of the lough has been improving steadily over the past few years. Nature finds a way ! Water clarity has greatly improved and this last season the lough bed could be observed clearly in eight feet of water. Also the fish seem to be rising more often due probably to the fact that they see flies at a greater distance. All in all, things are looking good for Lough Conn.