St. Mary Extra (an ancient parish) together with that of Sholing was formed in 1903 into the civil parish of Itchen At the time of the last Ordnance Survey, St. Mary Extra comprised 2,177 acres, and Sholing 597 acres. The parish is bounded on the west by the estuary of the Itchen and the upper reaches of Southampton Water, and runs some two miles inland, the levels sloping gently from a height of about 130 ft. on its eastern boundary to the tidal waters on the west The coast district is practically an outlying portion of Southampton, which threatens to encroach still further in this direction Source: https://www.british-history.ac.uk/vch/hants/vol3/pp297-299