1983–1997: The Borough of Test Valley wards of Abbey, Blackwater, Chilworth and Nursling, Cuppernham, Field, North Baddesley, Romsey Extra, and Tadburn, and the District of New Forest wards of Blackfield and Langley, Colbury, Dibden and Hythe North, Dibden Purlieu, Fawley Holbury, Hythe South, Marchwood, Netley Marsh, Totton Central, Totton North, and Totton South.

The constituency was approximate to the Test Valley district of Hampshire and covered a smaller area as parts of the north of Test Valley fell into part of the North West Hampshire seat to roughly ensure equal size electorates (low malapportionment).

It was originally named Romsey and Waterside and included areas such as Hythe and Fawley on the west side of Southampton Water.

In 1997 it lost the Waterside area and gained the Bassett Ward of the City of Southampton, and new territory in the north of the Test Valley district, and was consequently renamed to just Romsey.

This led to a by-election, which was won by Liberal Democrat Sandra Gidley, who held the seat in the two subsequent General Elections.