Portland was named after the Duke of Portland. It extends from the sea coast to the highest peak of the Blue Mountains and is noted for its fertility and the beauty of its scenery. It also experiences a significant amount of rainfall annually. The town of Port Antonio, which is also the parish capital, is located on the northern coast, approximately in the centre of the parish perimeter. Portland's ports gave it importance as a major export centre for bananas at the end of the 19th century and beginning of the 20th, whilst its scenery made it known as a select tourist destination. However, its distance from a major airport and the decline in the local banana exporting activities has limited its tourism development.

Port Antonio is a coastal town, surrounded at the back by the Blue Mountains. It stretches forward into the sea with two peninsulas, Titchfield and Folly Point, both of which shelter bays, the east and west harbours, from the dominant north-east winds. Just off to the north-west of Titchfield, Navy Island offers further protection to large ships.

Port Antonio has its main activities in the retailing, tourism and agricultural (banana, coffee and yam) sectors. Its administrative and commercial role in the parish is undisputed. Agriculture remains as the main economic activity of the parish.