The Bann forms the western boundary from where it issues out of Lough Neagh to the point where it enters Londonderry, a distance of about 27 miles.

The Lagan runs on the southern boundary from near Moira to its mouth, about 22 miles.

The Six-mile Water, flowing by Ballyclare into the northeast corner of Lough Neagh, near the town of Antrim.

The Larne Water, having its source near that of the Six-mile Water, but flowing in an opposite direction, falls into the sea at Larne.

The Main, running southward by Cullybacky, Galgorm, and Randalstown, into the northeast corner of Lough Neagh.

The Glenwhirry River and the Kells River, which form one stream, flowing west by Kells into the Main.

The Braid flows west, by Broughshane and Ballymena, into the Main.

The Glenravel Water and the Clogh River, forming one stream, flow southwest into the Main, near Clogh Mills.

The Bush flows north, by Armoy and Bushmills, into the sea near the Giant's Causeway.

The Carey and the Glenshesk, two mountain streams run into the sea at Ballycastle.

The Glendun, which falls into the sea at Cushendun; and near it on the south,

The Glenaan, running by Cushendall.

The Glenariff, flowing through a beautiful glen into Red Bay, near Cushendall.

The Glenarm River flowing by Glenarm.

A large portion of Lough Neagh belongs to this county.

Lough Beg, an expansion of the Bann, a little below Lough Neagh, about 3 miles long and ¾ mile wide, contains several islands.

Lough Guile, a small lake 7 miles east of Ballymoney, gives name to the surrounding parish:

Portmore Lake, between the southeast shore of Lough Neagh and the village of Ballinderry, circular, and about a square mile in area:

Lough Mourne, 3 miles north of Carrickfergus.