Saint John is in the north of Jersey and borders Saint Mary on its west, Trinity to the east, and Saint Lawrence and Saint Helier on its south. Saint John is the second least populated parish of Jersey, having only 2,618 residents as of 2001.
The cliffs of the parish's north coast afford some of the best views in Jersey. After Trinity, it has the second highest point in Jersey at Mont Mado (473 ft). The parish covers 4,846 vergées.
Mont Mado granite was quarried historically. The largest quarry is now that of Ronez on the north coast.
Route du Nord was constructed during the German Occupation as a scheme to provide work. The road is now dedicated to the men and women of Jersey who suffered from 1939-1945.
The parish is divided into vingtaines for administrative purposes as follows:
- Vingtaine du Nord
- Vingtaine de Hérupe
- Vingtaine du Douet
The parish is one electoral district and elects one Deputy.
St John is twinned with:
- Great Eastern Hotel Added 2016