[4] In 1896, an area in the south-west of the historic parish of Onchan became part of the borough of Douglas, since when it has been governed by a municipal corporation with 18 councillors and an elected mayor.

The coastline comprises the northern part of Douglas Bay and the Banks' Howe headland, which is 120 metres (390 ft) high.

The Groudle Glen Railway runs for a short distance along the coast from Lhen Coan to the Headland and then on to the terminus at Sea Lion Rocks, where passengers can alight and see the remains of the Victorian zoo which until World War II housed sea lions and polar bears.

Like the other parishes on the island, Onchan was historically subdivided into "treens": areas of land bounded by natural features such as rivers.

Some of the plants/trees that grow there are silver birch, ash, holly, rowan, marsh marigold, yellow flag, reed canary grass, hemlock water-dropwort, woody nightshade and cuckoo flower.

Among the wide variety of birds on the site are the grey wagtail, goldcrest, woodcock, chiffchaff and hen harrier.

Under the new system, the Island was divided into 12 constituencies based on population, with each area represented by two members of the House of Keys.