Down contains two significant peninsulas: Ards Peninsula and Lecale peninsula.

The county has a coastline along Belfast Lough to the north and Carlingford Lough to the south (both of which have access to the sea).
Strangford Lough lies between the Ards Peninsula and the mainland.
Down also contains part of the shore of Lough Neagh.
Smaller loughs include Lough Island Reavy.

The River Lagan forms most of the border with County Antrim.
The River Bann also flows through the southwestern areas of the county.
Other rivers include the Clanrye and Quoile.

There are several islands off the Down coast: Mew Island, Light House Island and the Copeland Islands, all of which lie to the north of the Ards Peninsula.
Gunn Island lies off the Lecale coast.
In addition, there are a large number of small islands in Strangford Lough.

County Down is where, in the words of the song by Percy French, "The mountains of Mourne sweep down to the sea", and the area around the granite Mourne Mountains continues to be known for its scenery.
Slieve Donard, at 849 m (2,785 ft), is the highest peak in the Mournes, in Northern Ireland and in the province of Ulster.
Another important peak is Slieve Croob, at 534 m (1,752 ft), the source of the River Lagan.
Down contains two significant peninsulas: Ards Peninsula and Lecale peninsula.
The county has a coastline along Belfast Lough to the north and Carlingford Lough to the south (both of which have access to the sea). Strangford Lough lies between the Ards Peninsula and the mainland. Down also contains part of the shore of Lough Neagh. Smaller loughs include Lough Island Reavy.
The River Lagan forms most of the border with County Antrim. The River Bann also flows through the southwestern areas of the county. Other rivers include the Clanrye and Quoile.
There are several islands off the Down coast: Mew Island, Light House Island and the Copeland Islands, all of which lie to the north of the Ards Peninsula. Gunn Island lies off the Lecale coast. In addition, there are a large number of small islands in Strangford Lough.
County Down is where, in the words of the song by Percy French, "The mountains of Mourne sweep down to the sea", and the area around the granite Mourne Mountains continues to be known for its scenery. Slieve Donard, at 849 m (2,785 ft), is the highest peak in the Mournes, in Northern Ireland and in the province of Ulster. Another important peak is Slieve Croob, at 534 m (1,752 ft), the source of the River Lagan.
County Down