Forbury Hill's flanks include a large cliff face one kilometre inland from the beach and a rocky headland which juts into the Pacific Ocean.
The inland cliff, which runs parallel with and to the west of Forbury Road, was the site of a quarry in the early days of the city.
A small stream runs from the flank of Forbury Hill, passing into a culvert before reaching the sea at the western end of St Clair Beach.
The beach at St Clair is backed by sea wall, behind which is an esplanade consisting of pedestrian walkway and a one-way street.
The beach and the dunes are often the victims of erosion if weather patterns see series of storms hit the city from the south.
Remedial work has to be frequently undertaken to shore up the dunes, and there is considerable local concern about the long-term viability of the residential area behind them.
These cliffs include hexagonal basalt columns, one of three such outcrops in Dunedin (the others being at Blackhead, further to the west, and at the Organ Pipes formation on Mount Cargill.
A popular 1000 metre-long walking track leads from behind the St Clair hot saltwater pool to cliffs at the head of Forbury Hill, along a ridge behind Second Beach.
The area has now been rewilded, with native species such as tī kōuka, taupata, ngaio, poroporo, hebe, and harakeke, alongside several introduced plants such as wild lupin and artemisia.
A distinctive feature of the area is a natural blowhole in the foot of Forbury Head, located close to the southwestern end of the walking track.
[10] Chinese settlers were notable among early residents in the St Clair area, and largely through their effort the swampy land inland from the beach was drained,[7] and converted into market gardens.
Much of the young city's vegetable production was centred on Chinese allotments in an area close to what is now Macandrew Road, Forbury.
Habitation remained sparse until the early twentieth century, but rapid growth immediately prior to World War I saw the population expand.
The suburb was largely populated by the city's more wealthy residents, with impressive houses by Francis Petre built close to the beach in Cliffs Road, two of which survive.
The cliffs above Second Beach were the site of a gun battery – part of a coastal defence system – from the 1880s until the end of World War I.
[13] The Esplanade was repaired, but erosion of the dunes immediately to the east continues, threatening the long-term viability of coastal properties in the vicinity.
The beach is also the site of the city's annual "midwinter plunge", which sees residents brave the chilly waters every year at the winter solstice.
One of the city's wealthier suburbs, many fine houses are situated in the upper part of St Clair on the slopes of Forbury Hill.