Saint John is one of Dominica's 10 administrative parishes. It is bordered by St. Andrew to the east, and St. Peter and the Espagnole River to the south. It has an area of 59 km².
5,897 people live in the parish, half of which live in the main settlement, Portsmouth. Glanvilla and Lagoon serve as the town's suburbs.
Other settlements include:
Coordinates 15°34'33.294" N -61°27'20.117" E