England is divided into the hill regions of the north, west, and southwest and the rolling downs and low plains of the east and southeast. Running from east to west on the extreme north Scottish border are the Cheviot Hills. The Pennine Range runs north and south from the Scottish border to Derbyshire in central England. The rest of the countryside consists mainly of rich agricultural lands, occasional moors, and plains. South of the Pennines lie the Midlands (East and West), a plains region with low, rolling hills and fertile valleys. The eastern coast is low-lying, much of it less than 5 m (15 ft) above sea level; for centuries parts of it have been protected by embankments against inundation from gales and unusually high tides. Little of the south and east rises to higher than 300 m (1,000 ft).
The highest point in England is Scafell Pike (978 m/3,210 ft) in the famed Lake District of the northwest. The longest of the rivers flowing from the central highlands to the sea are the Severn (about 340 km/210 mi) in the west and the Thames (about 320 km/200 mi) in the southeast. Other rivers include the Humber, the Tees, the Tyne, and the Tweed in the east, the Avon and Exe in the south, and the Mersey in the west.
Scotland has three distinct topographical regions: the Northern Highlands, occupying almost the entire northern half of the country and containing the highest point in the British Isles, Ben Nevis (1,343 m/4,406 ft), as well as Loch Ness, site of a fabled "monster"; the Central Lowlands, with an average elevation of about 150 m (500 ft) and containing the valleys of the Tay, Forth, and Clyde rivers, as well as Loch Lomond, Scotland's largest lake; and the Southern Uplands, rising to their peak at Merrick (843 m/2,766 ft), with moorland cut by many valleys and rivers.
Wales is largely mountainous and bleak, with much of the land suitable only for pasture. The Cambrian Mountains occupy almost the entire area and include Wales's highest point, Mt. Snowdon (1,086 m/3,563 ft). There are narrow coastal plains in the south and west and small lowland areas in the north, including the valley of the Dee.
Northern Ireland consists mainly of low-lying plateaus and hills, generally about 150 to 180 m (500–600 ft) high. The Mourne Mountains in the southeast include Slieve Donard (852 m/2,796 ft), the highest point in Northern Ireland. In a central depression lies Lough Neagh, the largest lake in the United Kingdom.
The United Kingdom's long and rugged coastline, heavily indented, has towering cliffs and headlands and numerous bays and inlets, among them the deep and narrow lochs and the wide firths of Scotland. Many river estuaries serve as fine harbors.