The town occupies a narrow corridor between water and mountain. To the west, Tolo Harbour opens across to the older urban fabric of Sha Tin. To the east, the twin peaks of Ma On Shan rise to 702 metres, their saddle-shaped silhouette giving the town its name and its most recognizable landmark. The town is technically part of Sha Tin District and began as an extension of Sha Tin New Town, but it has grown distinct enough to be classified separately in government reports. It stretches from Wu Kai Sha in the north to Tai Shui Hang in the south, the MTR Tuen Ma Line threading through its core. The original Ma On Shan Village, where miners and their families once lived in their thousands, still stands in the hills above — around 80 families remain.

The iron mine that had sustained the hillside community since 1906 closed in 1976. Three years later, the New Town development program began moving in the other direction — not emptying the landscape, but filling it. Public housing construction started in the mid-1980s. Heng On Estate, the first major public estate, was completed in 1987. Chevalier Garden, a private development, followed in 1988. The deposit of iron ore in the hillside was estimated at over 7 million tonnes in total; the iron extracted between the 1950s and 1970s went almost entirely to Japan for steel production. The new town that replaced the mining economy runs on a different kind of infrastructure: rail connections, shopping centres, schools, and a population of over 200,000 as of the 2016 census, 94% of them of Chinese ethnicity.

The azalea species Rhododendron hongkongense was first collected in Hong Kong between 1847 and 1851, when it was recognized as a new species. For nearly eight decades, however, it was classified under a different name. Only in 1930 did botanists formally give it the name it carries today — hongkongense — acknowledging its distinct Hong Kong identity. The species grows on Ma On Shan and a small number of nearby sites — its range is extraordinarily restricted. In April, it blooms in shades between white and light red against the green hillside. Since 2006, an annual Ma On Shan Azalea Festival has marked the flowering season, celebrating not just Rhododendron hongkongense but five other locally native azalea species. The festival has become part of the town's identity, a way of holding onto the natural landscape that surrounds the high-density housing on all sides.

The MTR Tuen Ma Line, which serves Ma On Shan's stations at Tai Shui Hang, Heng On, Ma On Shan, and the terminus at Wu Kai Sha, opened as the Ma On Shan line in December 2004 and merged with the wider network in 2021. It gives residents direct rail access to Hung Hom, where connections fan out across the MTR system toward the city, the border crossings, and Lantau Island. The town centre holds two connected shopping centres — Ma On Shan Plaza and MOSTown — and the Ma On Shan Sports Ground, swimming pool, and public library provide civic infrastructure for a population that is effectively urban but lives within sight of country park. The Yan Kwong Lutheran Church, revitalized in 2015 as a heritage centre (work began in 2014), keeps the mining era visible in a neighbourhood built almost entirely after the mine closed.