The county is situated mostly in the basin of the Erne, which divides the county into two nearly equal sections.
Trout are taken in most of the loughs, and pike of great size in the Loughs Erne.
Its surface is hilly, and its appearance (in many parts) somewhat sterile, though in the main, and especially in the neighbourhood of Lough Erne, it is picturesque and attractive.
It passes Belturbet, the Loughs Erne, Enniskillen and Belleek, on its way to the Atlantic, into which it descends at Bailyshannon.
One of these on the north side of Lough Erne is 15 m.