Geography

Northern Ireland is the smallest country in the United Kingdom, situated on the second largest island of the British Isles. It occupies one-sixth of the island it shares with the independent Republic of Ireland. Northern Ireland is composed of six of the twenty-nine counties of Ireland, covering about 5,452 square miles (14,120 square kilometers). It is separated from the Republic of Ireland by a three-hundred-mile-long artificial boundary. Northern Ireland makes up the northwestern corner of the island; the entire island is bordered on the west by the Atlantic Ocean, on the east by the Irish Sea, and on the south by the Celtic Sea. The waters around Northern Ireland's coast are shallow.

The climate is mild as a result of Atlantic Ocean breezes and the Gulf Stream, with comfortable summers and temperate winters. Snow is uncommon, and temperatures dip below freezing only a few times a year. However, rainfall is heavy. Low mountains with steep cliffs dropping off to the sea and fertile lowlands are the principal topographic features. The two major mountain ranges are the Sperrin Mountains and the Mourne Mountains. Most of the farmable land, in the middle of the country, is used as grazing pastures for livestock. Lough Neagh, in central Northern Ireland, is the largest lake in the British Isles.

Until seven thousand years ago, Ireland was linked to Europe by a land bridge, but the ocean eroded that bridge and separated Ireland from the continent. Scotland lies just thirteen miles east of the island across the English Channel.

The Upper Bann River begins in the Mourne Mountains and flows northwest for twenty-five miles before entering Lough Neagh. The Erne River, which is seventy-two miles long, starts in the Republic of Ireland and flows northward into Northern Ireland. The Foyle River, marking the northwestern boundary with the Republic of Ireland, passes through Londonderry and empties into the Atlantic Ocean, becoming a bay called Lough Foyle.