Geologically, the Cave Hill is at the southern end of the Antrim Plateau, which was largely formed about 65 million years ago (yes, just at the end of the age of the dinosaurs) by great lava eruptions that continued for millions of years. The basalt rock which resulted was worn down by subsequent ice ages and weathering into the smoother formations seen today.

The Cave Hill was formerly known as Ben Madigan, probably after a local chieftain who died in 855 AD. McArt's Fort is probably named after Art O'Neill, a sixteenth century chieftain of the family who held the land around Cave Hill. In 1603 this land was granted by King James 1 to Arthur Chichester, later the Earl of Donegall. There are five caves (four visible from below) which are man-made, cut from the basalt. The lowest is accessible from the Sheep's Path. The caves were not permanently occupied, but may well have been used as temporary refuges.

There are a number of sites of archaeological interest on the Cave Hill, dating back to the stone age. These include several ringforts (raths) and a lake dwelling (crannog) at Hazelwood. McArt's Fort is on the highest point which is popularly (but inaccurately) known as Napoleon's Nose. It is likely that this was used for ceremonial rather than defence purposes and it appears to date from about three thousand years ago.

The Cave Hill is the second most northerly of the Belfast Hills which will form the operational area of the Belfast Hills Partnership. The most northerly is Carnmoney Hill, and the other main hills, traveling southwards, are Squires Hill, Divis Mountain, Black Mountain, Collin and Slievenacloy. Most of this area is agricultural, with hill farming the main activity. The Belfast Hills range over four local authority areas, namely Antrim, Newtownabbey, Belfast and Lisburn. Only Cave Hill and Collin Glen have public park status, guaranteeing public right of access. The significance of this was brought into stark prominence when the annual Belfast Hills Walk from Collin Glen to Cave Hill, scheduled for Sunday 30 May 1999, had to be greatly shortened at the last moment due to the refusal of one farmer to allow the walk to cross two metres of his land. The walk was confined to Collin and Divis.

Most of the area of the Cave Hill is within the boundaries of the Cave Hill Country Park which, together with Belfast Castle, is owned by Belfast City Council. The Park comprises 750 acres of land. This public ownership protects the area from development and guarantees public right of access. It also gives Belfast City Council the main management responsibility for the Cave Hill.

The Hill contains a variety of habitats. These include heather moorland, rocky outcrops and mixed woodland. Most of the trees are less than 100 years old, but there are many mature specimens. There has been extensive planting of native species, especially oak, within the last 20 years. The trees are mostly deciduous - ash, beech, birch and rowan are numerous - but there is also a good population of mature scots pine. Smaller growing species include hazel, elder, hawthorn, blackberry and ferns. The area is rich in wild flowers - the better known species include bluebells, primroses, wild garlic, wood anemone, lesser celandine and herb robert. The hazlewood area above the zoo is one of the most important habitats on Cave Hill.

There is also a considerable range of wildlife. Mammal species include foxes, badgers, grey squirrels, hedgehogs, rabbits, shrews and bats. Bird species include owls, kestrels and sparrowhawks as well as the full range of woodland birds such as blackbirds, thrushes, finches, tits, robins, dunnocks and wrens. In summer, there are swallows and house martins. The heather moorland has skylarks, wheatears and pipits.

The Hill is popular with walkers and joggers. There are eight waymarked trails, which range from short easy strolls to challenging 5 mile treks over the summit. There are five access points - Hightown Road, Carrs Glen, Upper Cavehill Road, Belfast Castle and Hazelwood.